Ingredients
What does coal tar treat?
Psoriasis, dandruff and seborrheic dermatitis, mostly on the scalp. It is old, cheap and genuinely effective, and it smells and stains. Coal tar dyes are unrelated.
- Slows scalingPsoriasis, dandruff, seborrheic dermatitis
- Stains and smellsLight hair, towels, baths and fabric
- Burns more easilySun protection for a day after use
On this pageWhat it is approved to treat5
Quick answer
The bottom line
Coal tar is a recognised nonprescription treatment for scalp psoriasis, dandruff and seborrheic dermatitis, allowed in the United States at 0.5 to 5 percent depending on the preparation. It slows the overproduction of skin cells that drives scaling, and decades of use back it. The trade-offs are real: a strong smell, staining of light hair, fabric and baths, sensitivity to sunlight and occasional folliculitis. Use it on the scalp or body areas the label covers, wash it out as directed, and use sun protection afterwards. It is not a treatment for acne or for ordinary dry skin.
At a glance
Three things worth remembering
- "Coal tar dyes" on a cosmetic label is a naming convention for synthetic colourants, not this medicine.[6]
Section 01
What it is approved to treat
United States nonprescription rules list coal tar for dandruff, seborrheic dermatitis and psoriasis, at 0.5 to 5 percent depending on how the tar is prepared. That covers shampoos, ointments, creams and bath preparations. Dermatology guidance for scalp psoriasis keeps tar shampoo among the standard options, often alongside a scale softener.[1][2]
It is not an acne treatment, not a moisturiser and not something to use on broken or infected skin. Products aimed at the scalp are formulated to be washed out; body preparations are different, and the label tells you which you have.[3][5]
Section 02
How it works, in plain terms
In psoriasis, skin cells are produced far faster than they can be shed, and the pile-up becomes scale. Coal tar slows that production and reduces the inflammation and itch that come with it. That mechanism is why it helps scaling conditions specifically rather than dryness in general.[4][2]
For dandruff and seborrheic dermatitis the effect is similar, though antifungal shampoos containing ketoconazole or zinc pyrithione are usually tried first because they are pleasanter to use. Tar is a reasonable option when those have not been enough or when scaling is heavy.[5][1]
Section 03
The trade-offs nobody hides
It smells strongly, and the smell lingers. It stains: light, grey or chemically treated hair can pick up a yellow-brown tint, and it marks towels, pillowcases, clothing and bath surfaces. Using an old towel and rinsing the bath immediately are the practical answers.[3][2]
Coal tar increases sensitivity to sunlight, so exposed skin burns more easily for about a day after use. Labels say to limit sun exposure and use protection. Some people develop a folliculitis of small spots where it has been applied, which settles after stopping.[3][1]
Section 04
The safety question, answered honestly
Coal tar as an industrial exposure, breathed in and absorbed at high concentrations over working lifetimes, is a recognised cancer risk. That is where the concern originates, and it is a real one in that setting.[4][1]
Follow-up studies of people using tar preparations as medicines at label strengths have not found the same increase in skin or internal cancers. Those studies are observational, so our search found reassurance rather than proof. The practical reading most dermatology guidance takes: reasonable to use as directed for a scaling condition, not something to apply indefinitely without a reason.[4][2]
Section 05
Why your shampoo label says "coal tar dyes"
This is a separate matter that shares a name. Synthetic colourants were originally made from coal tar, and some regulators, Canada among them, still use "coal tar dyes" as the umbrella term for that family of colours even though they are now made from petroleum. Seeing the phrase in an ingredient list means colour, not medicine.[6]
If you are looking for the treatment, check the active ingredients panel rather than the ingredient list. A medicated product names coal tar as an active ingredient with a percentage; a cosmetic naming coal tar dyes is telling you how it was coloured.[6][3]
Your next step
Turn this into a practical plan
Choose the guide that best matches what you see. Each one starts with what to try, how long to wait and when to get help.