In this article
Coal tar is the oldest psoriasis treatment still in regular use — and the only ingredient on this site that is simultaneously a licensed medicine, a Group 1 carcinogen, and a drugstore shampoo. The contradiction dissolves once you separate dose from substance. The cancer classification comes from workers who spent years breathing and handling industrial coal tar and pitch at high concentrations, and from animals painted with it. The shampoo on a pharmacy shelf is a different exposure: 0.5% to 5% coal tar, rinsed off or applied to limited skin, for a condition with no cure. The largest study of that medical use, following 13,200 psoriasis and eczema patients, found no increased cancer risk. That is why the US FDA keeps coal tar on its over-the-counter monograph while California puts a cancer warning on the same bottle, and why Europe sells it as a medicine rather than as a cosmetic. Coal tar is not a story about a hidden poison. It is a story about an effective, unpleasant, old drug whose risk depends almost entirely on how much of it, for how long, and on how much skin — and about a warning label that tells you about the substance, not about your shampoo.
What coal tar is
Coal tar is not a single chemical with a formula. It is the thick, dark, strong-smelling liquid left over when bituminous coal is heated without air to make coke — the destructive distillation of coal, in the pharmacopoeia's phrase — and it contains thousands of compounds, among them polycyclic aromatic hydrocarbons (PAHs): rings of carbon formed by incomplete combustion, including benzo[a]pyrene, which the International Agency for Research on Cancer (IARC) classifies on its own as a Group 1 carcinogen. That complexity is the first thing to understand about every claim made for or against it. When a label says "coal tar", it names a variable mixture, not a pure substance, and different preparations — crude coal tar, coal tar solution, distilled coal tar, coal tar extract — differ in which fractions they keep and how concentrated they are. Two bottles with the same percentage on the front can therefore carry different amounts of the compounds people worry about, which is one reason regulators argue about this ingredient more than about most others on the flagged list.
The second thing to understand is that coal tar's medical career predates modern dermatology. Dermatologists have prescribed it for psoriasis for more than a century, and it remains in formularies today: NHS formularies list coal tar lotions, scalp ointments and shampoos for mild to moderate psoriasis and scalp psoriasis, alongside the note that preparations stain skin, clothing, baths and floors. It survives not because it is pleasant — nobody describes it as pleasant — but because it works on the symptoms that define psoriasis: scaling, itching and inflammation. Psoriasis has no cure, so a cheap topical treatment that controls symptoms for years, without the internal risks of systemic drugs, keeps its place even as newer treatments arrive.
Tip: Do not confuse coal tar with pine tar or juniper tar. Those wood tars were removed from the US over-the-counter dandruff, seborrhoeic dermatitis and psoriasis monograph in 1990 for lack of proof of effectiveness. A product labelled "tar" without the word "coal" is a different ingredient with a different regulatory history.
Why dermatologists still use it
Coal tar is thought to slow the rapid skin-cell growth that builds psoriasis plaques — by suppressing DNA synthesis in keratinocytes — while also reducing inflammation and itch. The modern explanation adds a receptor: PAHs in coal tar activate the aryl hydrocarbon receptor, a protein in skin cells and immune cells involved in the dysfunctional immune response behind psoriasis. The honest version is that the precise mechanism is still not fully established; what is established is the clinical effect, observed over a century of use and in comparative trials, including a randomised trial in which a leave-on coal tar solution outperformed prescription calcipotriol cream over 12 weeks. It is also cheap, it can be used long-term, and it avoids the internal side effects of systemic psoriasis drugs — the combination that keeps it as a first-line option for localised disease, for people without insurance, and for people who cannot use stronger prescription therapies.
Its most distinctive use pairs it with light. The Goeckerman regimen, introduced in 1925, combines crude coal tar with ultraviolet B (UVB) phototherapy: tar is a photosensitiser, so tar-treated skin responds more strongly to UVB, and the combination clears psoriasis better than either treatment alone. Modern Goeckerman therapy is given in day-care clinics — typically several hours a day, five days a week, for around six weeks — and remains, in the words of a patient guide to the regimen, one of the oldest and most reliable options for moderate to severe psoriasis. That same photosensitising property is also coal tar's most practical everyday hazard, as the sections below explain: the feature that makes the therapy work is the one that makes an afternoon in the sun after a morning shampoo a burn risk.
Where you will find it
- Medicated shampoos — the commonest form, for scalp psoriasis, seborrhoeic dermatitis and dandruff; usually left on for several minutes before rinsing, and often combined with salicylic acid, which softens scale so the tar reaches the skin
- Scalp lotions, ointments and gels — leave-on formats for plaques on the scalp, elbows, knees and palms, including combination products with a mild steroid
- Bath oils and bath additives — dilute tar dispersed in bath water for more widespread plaques
- Soaps and bars — a traditional format, still sold, for washing tar-treated skin
- As a medicine, not a cosmetic, in Europe — the same preparations that sit on a US drugstore shelf are licensed medicines in Ireland and the UK, prescribed or sold through pharmacies rather than as ordinary toiletries
Related: Sulfates: What SLS and SLES Do, Why People Avoid Them, and Gentler Options — most medicated shampoos, coal tar included, are built on a sulfate cleansing base, so the shampoo's base matters as much as its active if your scalp is already irritated.
The concern: a carcinogen in a shampoo bottle
The concern starts with the classification, and the classification is real. IARC's evaluation of coal-tar pitches — Supplement 7, 1987, confirmed in the 2012 monograph volume — places them in Group 1, carcinogenic to humans, on sufficient evidence in humans and in animals. The human evidence is occupational: a 1946 UK mortality analysis showing greatly increased scrotal cancer among patent-fuel workers, case reports of skin cancer in workers exposed to coal tars and pitch, excesses of lung and bladder cancer among workers exposed to pitch fumes in aluminium production, and a cohort of US roofers with increased lung cancer and suggested increases for cancers of the oral cavity, larynx, oesophagus, stomach, skin and bladder and for leukaemia. The animal evidence is direct: applying coal-tar pitches and their extracts to the skin of mice produced malignant skin tumours, and the extracts were mutagenic in bacterial tests. Nobody in the debate disputes this classification. The dispute is entirely about what it means for a shampoo.
The bridge between the occupational evidence and the bathroom is dose, duration and route — and the gap between them is enormous. A roofer or patent-fuel worker spent years with skin and lungs in daily contact with hot pitch fumes and raw tar; a shampoo user applies a 0.5% to 5% preparation to the scalp for minutes, then rinses it off. Animal studies that produced tumours used large amounts, repeatedly, over long periods. The question the therapeutic literature asks is whether the much smaller, intermittent, mostly rinse-off exposure still moves cancer risk measurably, and the largest answer to that question is reassuring — with a caveat that matters and that this article states rather than smooths over (see the regulators section). The everyday harms, by contrast, are not contested at all: coal tar irritates skin, can cause folliculitis — inflamed hair follicles, sometimes called tar acne — stains skin, light hair, clothing and bedding, smells strongly enough that many patients stop using it for that reason alone, and makes treated skin burn more easily. For most users, those are the effects they will actually experience, and they are the reason coal tar's use has declined even where nobody doubts its efficacy: patients vote against the smell and the staining, and dermatologists have noted that many of their colleagues abandoned tar for safety reasons even before the evidence was in.
What regulators and reviewers say
The United States treats coal tar as a drug, and its position is the most permissive. Under the over-the-counter monograph for dandruff, seborrhoeic dermatitis and psoriasis (OTC Monograph M032, restating 21 CFR Part 358, Subpart H), coal tar at 0.5% to 5% is recognised for controlling the symptoms of all three conditions, and a 1.8% coal tar solution combined with 1.5% menthol is recognised for dandruff shampoos. Real labels show how the percentages work: one psoriasis ointment is labelled coal tar 2% from a 20% coal tar topical solution, and a shampoo labelled 2.5% coal tar topical solution contains 0.5% coal tar. That two-number labelling is the commonest source of confusion on a coal tar pack, and it is worth learning: the solution percentage is not the coal tar percentage, and the coal tar percentage is the number the monograph's 0.5% to 5% range refers to. The FDA has defended this position directly. When a citizen petition asked the agency to restrict coal tar to prescription sale and add cancer warnings, the FDA reviewed the evidence and concluded, in its February 2002 response, that there was no evidence that topical treatment with over-the-counter coal tar shampoo, soap or ointment drug products increases the risk of skin cancers, and that no change in status was necessary.
California reached the opposite labelling conclusion from the same facts, and the story is instructive about how warnings work. Coal tar is on California's Proposition 65 list of chemicals known to cause cancer, and in 2000–2002 the state and a private plaintiff sued more than twenty manufacturers for selling coal tar products without the required warning. Most settled: cancer warnings went onto over-the-counter coal tar shampoos above 0.5% coal tar and onto lotions and creams, reading "Warning: This product contains chemicals known to the state of California to cause cancer", and most manufacturers applied the change nationwide rather than making a California-only pack. The National Psoriasis Foundation opposed the lawsuit, arguing that a warning would discourage patients from a safe, effective, inexpensive treatment or push makers to drop the ingredient; the FDA wrote on the manufacturers' behalf that there was no scientific evidence the tar in over-the-counter products is carcinogenic. Proposition 65 does not ban the products — it requires the warning — but a shopper who reads the warning without that history will reasonably conclude the shampoo is dangerous, which is exactly the confusion the Foundation warned about.
Europe takes a third route: medicine, not cosmetic, and not for sale to the general public as a chemical. Coal-tar distillates appear on the prohibited list (Annex II) of the EU Cosmetics Regulation 1223/2009, and carcinogenic coal-tar substances are restricted under REACH from sale to the general public at concentrations of 0.1% or more. The products that exist in Europe are therefore licensed medicines: an Irish summary of product characteristics for a 1% distilled coal tar shampoo, for example, licenses it for dry, scaly scalp conditions including seborrhoeic dermatitis, psoriasis and cradle cap, and states both that there is inadequate evidence of safety in pregnant and lactating women and that no studies have demonstrated an increased risk of skin cancer with normal therapeutic use in humans, with no unequivocal evidence linking topically applied coal tar products with skin cancer. Australia's chemicals assessment programme reached a similar framing in its tier II assessment: coal tar and coal tar pitch are industrial chemicals with worker-health controls, listed on Health Canada's prohibited and restricted cosmetic ingredients list, and restricted under REACH — a chemicals story, not a toiletries story.
The patient evidence that holds these positions together is the Dutch cohort study published in the Journal of Investigative Dermatology in 2010. Roelofzen and colleagues followed 13,200 patients with psoriasis and eczema, comparing those treated with coal tar against patients treated with dermatological corticosteroids, a reference group assumed to carry no increased cancer risk. The median exposure to coal tar ointments was 6 months, ranging from 1 to 300 months, and the median follow-up was 21 years. Coal tar did not increase the risk of non-skin malignancies (hazard ratio 0.92, 95% confidence interval 0.78–1.09) or of skin cancer (hazard ratio 1.09, 95% confidence interval 0.69–1.72), and the authors concluded the study had sufficient power to show that coal tar treatment is not associated with an increased risk of cancer, and that it can be maintained as a safe treatment in dermatological practice. Read the skin-cancer interval honestly: 1.09 means the best estimate is a 9% higher risk, and the interval runs from 31% lower to 72% higher, so the study rules out a large increase but cannot exclude a modest one. That is also why patient guidance from the National Psoriasis Foundation pairs its reassurance with a practical instruction: anyone using coal tar regularly should follow a regular skin-cancer check-up schedule. The advocacy database EWG Skin Deep (labelled here as an advocacy source, not a regulator) takes the hazard side of the same evidence: it rates coal tar HIGH for cancer and HIGH for use restrictions, moderate for allergies and immunotoxicity, and lists it as unacceptable for its verified mark. EWG's profile is a hazard ranking — it scores what a substance can do in principle — while the FDA and Roelofzen assessments are risk assessments, which ask what it does at a real dose. The difference between those two questions is the whole debate in miniature.
The debate
The case for caution
A Group 1 carcinogen is a Group 1 carcinogen, and the argument that "the dose makes the poison" is only comforting until you ask who controls the dose. Coal tar is a variable mixture, not a pure chemical, so the amount of benzo[a]pyrene and other PAHs in any given bottle is not printed on it; patients apply it themselves, sometimes for years, sometimes over large areas, sometimes without a doctor involved at all, because the shampoo sits on an open shelf. The largest reassuring study had a median exposure of only six months, its skin-cancer interval still allows a 72% higher risk, and it compared tar users with steroid users rather than with untreated people. On this view, a warning label is the minimum honesty: if a substance is listed as known to cause cancer, the person rubbing it into their scalp is entitled to know, and the fact that the FDA disagrees with California is a reason to distrust the reassurance, not the warning.
The case for reassurance
No study of therapeutic coal tar use has demonstrated an increased cancer risk in people, and the largest one — 13,200 patients, 21 years of follow-up — found none, with enough statistical power to say so. The occupational evidence that drives the classification involves exposures orders of magnitude higher, over working lifetimes, by inhalation as well as skin contact; equating that with a shampoo left on for five minutes is a category error, and the FDA's own review reached the same conclusion when it was asked to act. On this view, the California warning is the problem, not the solution: it frightens people away from one of the cheapest, longest-proven psoriasis treatments, for a risk that has not been shown to exist at therapeutic doses, while the real, demonstrated harms of untreated psoriasis — and of stronger systemic drugs — go unmentioned. The sensible precaution is a skin check-up schedule, not abandoning the treatment.
The position this site takes follows the patient evidence rather than either slogan: therapeutic coal tar at 0.5% to 5% has not been shown to increase cancer risk, the occupational classification is real but describes a different exposure, and the honest uncertainty — a modest skin-cancer increase that the best study cannot exclude — is best handled by using coal tar under guidance, keeping it off broken skin and out of the sun, and keeping up skin checks, rather than by either ignoring the warning or treating it as a verdict. And the everyday trade-offs deserve as much weight as the cancer question in a real decision: if the smell and staining mean you will not use it, it is not the right treatment for you, whatever the hazard ratios say.
Who should avoid it, or ask first
- People who are pregnant or breastfeeding — the American Academy of Dermatology advises they might prefer to avoid coal tar because research in this area is limited; licensed product information agrees the evidence is inadequate, while noting many years of use without apparent ill-consequence, so this is a conversation with your doctor, not a settled ban
- People who are sun-sensitive, or who take medicines that increase sun sensitivity — the Academy advises a different treatment here, because coal tar's photosensitising effect stacks with other sun sensitivity and turns ordinary sun exposure into a burn risk
- People using it over large areas, for long periods, without supervision — the reassuring evidence covers therapeutic use, mostly for months rather than decades of whole-body application; extensive or prolonged use belongs under a dermatologist's eye, with the regular skin-cancer check-ups patient guidance recommends
- People with broken, inflamed or infected skin in the area to be treated — tar irritates, and formulary guidance for combination tar creams advises avoiding mucosae and broken skin; a flare that is weeping or infected needs assessment before any tar goes on it
- Anyone who will not tolerate the practical costs — the smell, the staining of skin, light hair, sheets and baths, and the dryness and brittleness it can cause in hair are the commonest reasons people stop, and a treatment that sits unused in the shower helps no one
How to spot coal tar on a label
- Coal Tar — the name on US Drug Facts panels, where it appears as an active ingredient with its percentage (0.5% to 5% under the monograph)
- Coal Tar Topical Solution, USP — a solution form whose percentage is higher than the coal tar it delivers: 2.5% solution means 0.5% coal tar, and 20% solution means 2% coal tar in the finished product, so read the "equivalent to" line, not the big number
- Liquor Carbonis Detergens (LCD) — the traditional pharmacy name for coal tar solution, still seen on older and compounded preparations
- Distilled Coal Tar / Coal Tar Extract — refined forms used in some shampoos and lotions, including the 1% distilled coal tar in licensed European shampoos
- Crude Coal Tar (CCT) — the unrefined form used in Goeckerman therapy and in stronger ointments, usually under supervision rather than from a shelf
- The California warning — "Warning: This product contains chemicals known to the state of California to cause cancer" on products above 0.5% coal tar; its presence tells you the product is listed under Proposition 65, not that the FDA considers it unsafe
- Its usual companions — Salicylic acid (softens scale), menthol (the recognised 1.8% solution plus 1.5% menthol dandruff combination), and mild steroids in combination creams; pine tar or juniper tar on a label is a different ingredient, not coal tar
Related: Best Shampoo Without Sulfates: A Label-First Guide — if a coal tar shampoo's cleansing base is also irritating your scalp, this guide shows how to judge a shampoo by its whole label, not just its active.
Alternatives: the same symptom relief, without tar
The honest alternative depends on which condition you are treating, because coal tar covers three of them. For psoriasis, the other over-the-counter active recognised by the FDA is salicylic acid at 1.8% to 3%: it softens and removes scale, and it is often combined with coal tar itself, but on its own it does not carry coal tar's anti-itch and anti-inflammatory effects. Prescription topicals step up from there — topical steroids and vitamin D analogues such as calcipotriol, which the randomised trial above used as its comparator — and narrowband UVB phototherapy gives the light half of Goeckerman therapy without the tar. For dandruff and seborrhoeic dermatitis, the mechanism is different: antifungal shampoos with ketoconazole, zinc pyrithione or selenium sulfide target the yeast component that drives flaking, and for many people with dandruff rather than psoriasis they are the more direct answer. What none of these does is reproduce coal tar's particular combination — anti-itch, anti-inflammatory and scale-slowing in one cheap topical — which is why the alternatives list reads as a menu by condition rather than a single swap, and why a dermatologist's advice matters more here than for most ingredients on this site: the right replacement depends on the diagnosis, not just on the desire to avoid one ingredient.
Frequently asked questions
Does coal tar cause cancer?
Coal-tar pitch is classified by IARC as carcinogenic to humans (Group 1) on the basis of occupational and animal evidence. But the largest study of dermatological use — 13,200 psoriasis and eczema patients — found no increased risk of skin cancer (hazard ratio 1.09, 95% confidence interval 0.69–1.72) or of non-skin cancers (hazard ratio 0.92). That is evidence of no detected increase at therapeutic doses, not proof that no risk exists: the skin-cancer interval still includes values up to 72% higher.
Why does my coal tar shampoo carry a cancer warning if the FDA says it is safe and effective?
Because the two statements answer different questions under different laws. California's Proposition 65 requires a warning on products containing a listed carcinogen above the state's threshold, and coal tar is listed; after a 2000–2002 lawsuit, most makers agreed to warn on products above 0.5% coal tar. The FDA, applying its drug standard, concluded there was no evidence that over-the-counter coal tar at 0.5% to 5% increases skin-cancer risk, and it opposed the warnings. Both can be on the same bottle without either being a lie.
Is coal tar banned in Europe?
Not as a medicine, but it is not a cosmetic ingredient there. Coal-tar distillates appear on the prohibited list (Annex II) of the EU Cosmetics Regulation, and carcinogenic coal-tar substances are restricted from sale to the general public at 0.1% or more under REACH. The coal tar products sold in Europe — shampoos, lotions and ointments — are licensed medicines, not cosmetics, which is why the same ingredient can be a drugstore shampoo in the US and a pharmacy medicine in Ireland or the UK.
Can I use coal tar while pregnant or breastfeeding?
Guidance leans to avoiding it, not because harm has been shown but because the evidence is thin. The American Academy of Dermatology advises that pregnant or breastfeeding women might prefer to avoid coal tar because research in this area is limited. A licensed product's summary of characteristics puts it the same way: inadequate evidence of safety in pregnancy and lactation, but many years of use without apparent ill-consequence. Ask your doctor rather than deciding from the label alone.
Does coal tar make skin more sensitive to sunlight?
Yes. Coal tar is a photosensitiser: it makes treated skin burn more easily in sunlight or UVB light, and patient guidance says it remains active on the skin for at least 24 hours after application. That property is deliberately exploited in Goeckerman therapy, where coal tar plus UVB clears psoriasis better than either alone — but outside a clinic it means washing the product off thoroughly, using sunscreen, and watching sun exposure after use.
What can I use instead of coal tar for scalp psoriasis or dandruff?
For psoriasis, the other over-the-counter active recognised by the FDA is salicylic acid at 1.8% to 3%, which softens and removes scale; prescription options include topical steroids and vitamin D analogues, and narrowband UVB phototherapy. For dandruff and seborrhoeic dermatitis, antifungal shampoos with ketoconazole, zinc pyrithione or selenium sulfide target the yeast component rather than the scaling. None of these is a like-for-like swap: coal tar's combination of anti-itch, anti-inflammatory and scale-slowing effects is why it survives alongside newer options.
Checked against FDA OTC Monograph M032 and 21 CFR Part 358 Subpart H, the IARC Supplement 7 evaluation of coal-tar pitches, Roelofzen et al. 2010, the Irish summary of product characteristics for a licensed coal tar shampoo, National Psoriasis Foundation guidance, and the EWG Skin Deep database (an advocacy source) · Last updated 2026-11-02 · How we assess ingredients
Sources (11)
- DailyMed (US National Library of Medicine) — MG217 Psoriasis Medicated Multi-Symptom coal tar ointment, Human OTC Drug Label (updated 20 March 2026): active ingredient coal tar 2% (from Coal Tar Topical Solution, USP 20%), purpose psoriasis, seborrhoeic dermatitis and dandruff treatment; marketing category OTC Monograph Drug M032
- 21 CFR Part 358, Subpart H — Drug products for the control of dandruff, seborrhoeic dermatitis, or psoriasis (§358.710 active ingredients): coal tar 0.5 to 5 percent for dandruff, seborrhoeic dermatitis and psoriasis; when a coal tar solution, derivative or fraction is used, labelling must specify the source and the concentration of coal tar in the final product; permitted combination of 1.8% coal tar solution with 1.5% menthol in shampoo
- IARC Monographs, Supplement 7 (1987) — Coal-tar pitches (Group 1): sufficient evidence for carcinogenicity to humans (1946 UK mortality analysis showing greatly increased scrotal cancer among patent-fuel workers; skin cancer case reports in exposed workers; lung and bladder excesses among pitch-fume-exposed aluminium workers; US roofers cohort with increased lung cancer) and sufficient evidence in animals (malignant skin tumours in mice painted with coal-tar pitches or extracts); overall evaluation: coal-tar pitches are carcinogenic to humans (Group 1)
- Roelofzen JHJ, Aben KKH, Oldenhof UTH, et al. — No increased risk of cancer after coal tar treatment in patients with psoriasis or eczema. Journal of Investigative Dermatology, 2010;130(4):953-961: 13,200 patients with psoriasis and eczema; median exposure to coal tar ointments 6 months (range 1–300 months); coal tar did not increase the risk of non-skin malignancies (hazard ratio 0.92; 95% confidence interval 0.78–1.09) or skin cancer (hazard ratio 1.09; 95% confidence interval 0.69–1.72); authors conclude the study has sufficient power to show coal tar treatment is not associated with an increased risk of cancer and can be maintained as a safe treatment in dermatological practice
- Health Products Regulatory Authority (Ireland) — Summary of Product Characteristics, Capasal Therapeutic Shampoo (licence PA23128/008/001, 11 June 2024): distilled coal tar 1.0% w/w with salicylic acid 0.5% and coconut oil 1.0%; licensed for dry, scaly scalp conditions including seborrhoeic eczema, seborrhoeic dermatitis, pityriasis capitis, psoriasis and cradle cap; inadequate evidence of safety in pregnant and lactating women but preparations in use for many years without apparent ill-consequence; no studies demonstrating an increased risk of skin cancer with normal therapeutic use in humans and no unequivocal evidence linking topically applied coal tar products with skin cancer
- National Psoriasis Foundation OTC topicals guidance, as reproduced by Pharmacalway — A closer look at coal tar and salicylic acid: coal tar and salicylic acid are the two active ingredients approved by the FDA for psoriasis; tar slows rapid skin-cell growth and reduces inflammation, itching and scaling; tar can stain clothing, bed linen and light-coloured hair; tar makes skin more sensitive to sunlight, remains active on the skin for at least 24 hours, and users should wash it off thoroughly, use sunscreen and monitor sun exposure; studies show some chemicals in coal tar may cause cancer only in very high concentrations such as industrial paving; California requires OTC coal tar shampoos, lotions and creams above 0.5% coal tar to carry cancer warnings, while the FDA maintains OTC products at 0.5% to 5% are safe and effective for psoriasis with no scientific evidence that the tar in OTC products is carcinogenic
- National Psoriasis Foundation lawsuit bulletins, reprinted by Dave's Psoriasis Info — Coal Tar Lawsuit #8 (January 2002): following settlement of the California Proposition 65 lawsuit, most makers of coal tar products agreed to place the statement "Warning: This product contains chemicals known to the state of California to cause cancer" on their products, with warnings on lotions and creams by 20 February and on shampoos by 31 March; the FDA and the National Psoriasis Foundation submitted letters stating there is no scientific evidence that coal tar products cause cancer and that the FDA considers OTC coal tar at 0.5% to 5% safe and effective for psoriasis; Proposition 65 does not prohibit the sale of any coal tar products
- American Academy of Dermatology guidance on coal tar for psoriasis, as summarised by Medical Academic: dermatologists have prescribed coal tar for over 100 years; it is considered safe for long-term use and costs less than most psoriasis treatments; it can treat plaque-type psoriasis, itch, scalp psoriasis and difficult-to-treat palmoplantar psoriasis; people who are sun-sensitive or take medicine that makes them more sensitive to ultraviolet light should use a different treatment, as should pregnant or breastfeeding women
- The Patient's Guide to Psoriasis Treatment, Part 4: Goeckerman Therapy (Springer Medizin): the Goeckerman regimen, first introduced in 1925, combines ultraviolet B light with crude coal tar; tar is a photosensitiser and combined with UVB acts synergistically to produce better results than either treatment alone; modern outpatient treatment requires 4–5 hours a day, 5 days a week for 6 weeks (30 treatment days) at the UCSF Psoriasis Center; most commonly observed side effects are mild folliculitis and mild skin burning from UVB, and patients are advised to avoid extended sun exposure when tar is applied at home
- EWG Skin Deep cosmetics database (advocacy source) — Coal Tar ingredient profile: coal tar is a thick liquid or semi-solid obtained as a by-product in the destructive distillation of bituminous coal; concerns rated HIGH for cancer and HIGH for use restrictions, MODERATE for allergies and immunotoxicity, with high contamination concerns; unacceptable for EWG Verified products; cites IARC, the US National Toxicology Program and the US EPA as listing coal tar as a known human carcinogen, and names benzo[a]pyrene among its chemicals of concern
- Australian Industrial Chemicals Introduction Scheme (formerly NICNAS) — IMAP Group Assessment Report, Coal Tar and Coal Tar Pitch: Human health tier II assessment (13 February 2015): coal tar (CAS 8007-45-2) and coal tar pitch; notes the chemicals as "coal tars crude and refined" are listed in Health Canada's List of prohibited and restricted cosmetic ingredients, and are restricted under REACH Annex XVII such that the chemical cannot be used in substances and preparations placed on the market for sale to the general public in individual concentrations of 0.1% or more; companion IMAP assessment of coal tar distillates notes those substances are listed in EU Cosmetics Regulation 1223/2009 Annex II (prohibited in cosmetic products)
