Coal Tar Treatment for Psoriasis: How It Works, Evidence & What to Expect

Coal tar treatment for psoriasis has been used by dermatologists for well over a century, long before biologics, vitamin D analogues, or oral systemic drugs existed. Despite the arrival of far more advanced options, coal tar is still prescribed today for plaque psoriasis and scalp psoriasis because it is inexpensive, widely available, and has a long track record of safety when used correctly. This guide explains what coal tar actually is, how it is thought to work, what the evidence says about its effectiveness, its side effects (including the much-debated cancer question), how to find it in India, and how it fits into an Ayurvedic or integrative approach to psoriasis care.

What Is Coal Tar?

Coal tar is obtained by the destructive distillation of bituminous coal at very high temperatures — a byproduct of coal processing that has been used medicinally since the 1800s, making it one of the oldest continuously used treatments in all of dermatology. It is not a single chemical but an extremely complex mixture of thousands of compounds, mainly hydrocarbons, along with smaller amounts of phenols and other substances. Because of this complexity, coal tar has never been reduced to one isolated “active ingredient” the way most modern psoriasis drugs have. For skin use, it is typically formulated at concentrations between about 0.5% and 5% in over-the-counter and prescription products, while “crude coal tar” used under medical supervision in clinics can go up to around 10–20%.

How Does Coal Tar Work?

More than a hundred years after its introduction, the precise mechanism of coal tar in psoriasis is still not completely understood. Dermatology reviews generally describe three main effects: a keratoplastic or antiproliferative action that helps normalize the rapid skin cell turnover responsible for psoriasis plaques, a mild anti-inflammatory effect, and an antipruritic (itch-relieving) effect. Coal tar is also thought to have a mild antimicrobial action on the skin surface. Unlike targeted biologics that block a single inflammatory pathway, coal tar appears to act on several fronts at once, which may be part of why it has remained clinically useful even though science still cannot fully explain it.

Who Is Coal Tar Used For, and What Forms Does It Come In?

Coal tar is used for chronic plaque psoriasis on the body, and it is especially popular for scalp psoriasis, where it is formulated into medicated shampoos that patients use in place of a regular shampoo. It is also available as lotions, creams, ointments, gels, and bath additives for widespread or stubborn plaques, including on the palms and soles. Scalp shampoos (commonly containing around 1% coal tar, sometimes combined with salicylic acid) are the most accessible starting point for most patients and are explained in more detail in our guide to psoriasis shampoos for the scalp. Coal tar is generally considered appropriate for mild-to-moderate psoriasis and is frequently used as a first-line or adjunct therapy before escalating to stronger prescription options.

How Effective Is Coal Tar for Psoriasis?

Clinical experience with coal tar spans decades, but rigorous modern trial data is more limited than for newer drugs, partly because coal tar predates the current standards for clinical trials. Interestingly, effectiveness does not appear to simply scale with concentration: dermatology sources note that in at least one trial, a lower-strength 1% coal tar lotion performed better than a 5% formulation, suggesting that higher concentrations are not automatically more effective and may simply cause more irritation. Many patients see a meaningful reduction in scaling, redness, and itching, with some achieving extended symptom-free periods, particularly when coal tar is combined with a topical corticosteroid or with ultraviolet light rather than used strictly alone.

Goeckerman Therapy: Coal Tar Combined With UVB

The best-documented way to maximize coal tar’s effect is the Goeckerman regimen, first described in 1925, which combines crude coal tar (roughly 1–10%) applied to the skin with controlled exposure to ultraviolet B (UVB) light. Traditionally delivered as a daily inpatient or day-care program over two to four weeks, it has produced some of the longest documented remission periods of any psoriasis therapy, in patients who respond. Modern, outpatient-adapted versions of the regimen still exist in some specialized centers, though the time commitment and logistics mean it has become less common as biologics and oral systemic drugs have taken over as first-choice options for more extensive disease.

Side Effects and Safety Considerations

Coal tar has what dermatology sources describe as an excellent long-term safety record for topical use, but it does come with some practical downsides that patients should know about in advance:

• Skin irritation: stinging, burning, redness, or acne-like breakouts (folliculitis) at the application site, especially at higher concentrations.
• Staining and odor: coal tar can stain skin, light-colored or bleached hair, clothing, and bedding, and has a distinctive tar-like smell that some patients find unpleasant.
• Photosensitivity: treated skin becomes more sensitive to sunlight and UV exposure, so sun protection over treated areas is generally advised, and tanning beds should be avoided during treatment.
• Rare paradoxical worsening: uncommonly, coal tar can irritate psoriasis rather than improve it, in which case it should be stopped and the reaction reported to the treating doctor.
• Pregnancy and breastfeeding: data on fetal and infant exposure is limited, so most clinicians suggest alternatives during pregnancy or while breastfeeding unless specifically advised otherwise.

The question patients ask most often is whether coal tar is carcinogenic. Animal studies using very high, concentrated exposures have shown an increased skin cancer risk, and this is why some regions, including California under Proposition 65, require cancer-warning labels on coal tar products. However, large human studies have told a different story: a cohort study following more than 13,000 psoriasis and eczema patients for a median of 21 years found no increased risk of either skin cancer or non-skin cancers in patients treated with coal tar compared with those treated with topical corticosteroids alone. Based on data like this, major dermatology bodies continue to consider coal tar an appropriate, low-risk option for long-term topical use in humans, even though the warning labels persist for regulatory reasons rooted in the older animal data.

Is Coal Tar Available in India? Cost Considerations

Coal tar-based products are easily available in India, both over the counter and through pharmacies, without the cost burden of biologics or newer oral drugs. Medicated shampoos containing around 1% coal tar (such as Tar 18) are sold for roughly ₹300–400 per 100 ml bottle, and coal tar is also combined with salicylic acid in some shampoo formulations aimed at scalp psoriasis and seborrheic dermatitis. Coal tar creams, lotions, and ointments are similarly inexpensive compared with topical vitamin D analogues or biologic injections, which makes coal tar one of the more accessible entry points for managing mild-to-moderate psoriasis, particularly scalp involvement. As with any psoriasis product, exact prices vary by brand, pack size, and pharmacy, and should be confirmed at the time of purchase. For a fuller picture of how coal tar compares with topical, oral, and biologic costs, see our psoriasis treatment cost guide.

How Coal Tar Fits Into Ayurvedic and Integrative Psoriasis Care

Coal tar works locally — calming the plaque itself through its antiproliferative and anti-inflammatory action on the skin — but, like most topical treatments, it does not address the deeper systemic and constitutional factors that Ayurveda considers central to why psoriasis develops and recurs, such as digestive function, accumulated toxins (ama), and individual dosha imbalance.

In our clinical experience, patients already using a coal tar shampoo or ointment prescribed by their dermatologist often do well when Ayurvedic management is layered in alongside it rather than instead of it: internal herbal formulations and dietary correction aimed at the underlying trigger, combined with external applications that support and soothe the skin barrier, while the coal tar product continues to manage visible scaling and itching locally.

At our Ayurvedic psoriasis clinic in Bangalore, Dr. Chaithanya KS routinely coordinates this kind of integrative plan with patients’ treating dermatologists, with the long-term goal of reducing dependence on topical medication as the underlying trigger pattern is addressed. If you are weighing conventional and Ayurvedic approaches more broadly, our Ayurveda vs Allopathy comparison walks through that decision in more depth.

This article is for general education and does not replace a consultation with a qualified dermatologist. Coal tar products vary widely in strength and formulation; the right product, concentration, and duration of use should always be determined by your treating doctor based on your specific skin condition.

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Frequently Asked Questions

Sources

1. Psoriasis Treatment: Coal Tar. American Academy of Dermatology.
2. Coal Tar. DermNet NZ.
3. No Increased Risk of Cancer After Coal Tar Treatment in Patients With Psoriasis or Eczema. Journal of Investigative Dermatology.
4. Coal Tar Therapy: Is It Carcinogenic? PubMed.
5. Review of the Mechanism of Action of Coal Tar in Psoriasis. Journal of Dermatological Treatment.
6. Coal Tar: What Does It Treat and Is It Safe to Use? Medical News Today.