bishop seeds

The Health Benefits of Bishop’s Weed

Used to treat skin issues, supporting research is lacking

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Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman’s World, and Natural Health.

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Meredith Bull, ND, is a licensed naturopathic doctor with a private practice in Los Angeles. She helped co-author the first integrative geriatrics textbook, “Integrative Geriatric Medicine.”

Verywell / Anastasia Tretiak

Bishop’s weed (Ammi majus) is a common garden plant sometimes used in herbal medicine. It is most often used in the treatment of skin disorders such as psoriasis and vitiligo because it contains a compound that may help skin be more responsive to light therapy.

But despite bishop’s weed’s purported health benefits, there is limited scientific evidence to support its medical use.

Also Known As

  • Bishop’s flower
  • Lace flower
  • Lady’s lace

The term bishop’s weed is actually used to refer to several similar plants. Ammi majus should not be confused with Trachyspermum ammi (a.k.a. ajwan or carom) or Ammi visnaga (a.k.a. khella).

Health Benefits

People have been using bishop’s weed to treat health conditions as far back as 2000 B.C. in Egypt. However, more research is needed to determine whether the herb can confidently be recommended for the treatment of any health concern.

But given bishop’s weed’s composition, there is reason to think it could have some utility, particularly for skin conditions.

Skin Conditions

Bishop’s weed contains methoxsalen, a compound used in the treatment of such skin conditions as psoriasis, tinea versicolor, and vitiligo. Methoxsalen is classified as a psoralen, a type of compound that increases the skin’s sensitivity to ultraviolet light.

When taken orally or applied directly to the skin, methoxsalen is known to alter skin cells in a way that promotes the production of melanin (a natural substance that gives color to the skin) in response to ultraviolet (UV) light exposure.

Light therapy (phototherapy) uses UV light to treat a variety of skin conditions, as it can help reduce inflammation and slow skin cell growth. One of the three main types of phototherapy—psoralen-UVA (PUVA) therapy—involves given patients methoxsalen and then exposing them to ultraviolet light. PUVA therapy is typically used in the treatment of such conditions as eczema, psoriasis, vitiligo, and cutaneous T-cell lymphoma.

Today, prescription drugs used in PUVA therapy generally contain methoxsalen produced in the laboratory rather than compounds sourced from bishop’s weed.

Anti-Viral Properties

A preliminary study on bishop’s weed published in Organic and Medicinal Chemistry Letters in 2012 found that coumarins, compounds in bishop’s weed, may help reduce inflammation and fight off viruses.

In addition to these, bishop’s weed contains biologically active flavonoids that have antimicrobial properties, according to a 2019 study. That study also isolated a fungus from the fruit of bishop’s weed—Aspergillus amstelodami—that was found to have antimicrobial properties.

Possible Side Effects

Because few studies have tested the health effects of dietary supplements containing bishop’s weed, little is known about the safety of regular or long-term use of this herb.

There is at least some concern that bishop’s weed may trigger such side effects as headache, nausea, and vomiting. It also poses some more specific concerns, such as the following.


Since bishop’s weed changes the way your skin cells react to ultraviolet light exposure, the herb may increase sensitivity to the sun and, in turn, raise your risk of skin cancer.

If taking bishop’s weed, it is recommended to avoid prolonged periods of sun exposure. Wear sunscreen and, ideally, protective clothing whenever going outdoors.

Bishop’s weed should not be used with drugs that cause photosensitivity, including Elavil, (amitriptyline), Cipro (ciprofloxacin), Noroxin (norfloxacin), Maxaquin (lomefloxacin), Floxin (ofloxacin), Levaquin (levofloxacin), and tetracycline, among others.

Of note, a folk remedy for vitiligo involves mixing bishop’s weed, a little honey, and olive oil, applying it to the skin, and spending 10 minutes in the late-day sun. However, this is not recommended as it can result in phytophotodermatitis, a painful skin reaction that results in blisters and scarring 24 to 48 hours after exposure.

Blood Clotting Issues

The herb may also slow blood clotting and should not be taken along with other medications that slow clotting, such as aspirin, Plavix (clopidogrel), diclofenac, Advil (ibuprofen), Aleve (naproxen), Lovenox (enoxaparin), Coumadin (warfarin), and heparin.

Tell your doctor if you take bishop’s weed prior to surgery. They may recommend that you stop taking the herb in advance of any surgical procedure due to the risk of bleeding.

Liver Concerns

Pre-existing liver conditions may be worsened with the use of bishop’s weed, so people with liver problems should speak to their doctor before taking the herb.

In addition, anyone taking medications changed by the liver should use caution when taking bishop’s weed. These drugs include Mevacor (lovastatin), Nizoral (ketoconazole), Sporanox (itraconazole), Allegra (fexofenadine), and Halcion (triazolam), among others.

Pregnant women should not take bishop’s weed as it may cause uterine contractions that threaten the pregnancy. In addition, children and nursing mothers should not use bishop’s weed as safety in these populations has not been established.

Selection, Preparation & Storage

Because there isn’t enough scientific evidence to support the use of bishop’s weed for any health issues, there is no recommended dose. Follow the instructions on the product label and speak to your healthcare provider about what may be right for you.

When purchasing bishop’s weed, check the label for its scientific name, Ammi majus, so as not to accidentally purchase ajwain or khella.

Supplements are largely unregulated in the United States and not assessed for safety by the U.S. Food and Drug Administration (FDA). In some cases, a product may deliver doses that differ from the specified amount for each herb. In other cases, a product may be contaminated with other substances such as metals.

To ensure quality, look for supplements that have been tested and approved by an independent third-party certifying body like the U.S. Pharmacopeia (USP), ConsumerLab, or NSF International.

Common Questions

Is bishop’s weed a spice?
Ammi majus is not a spice. However, Trachyspermum ammi is an Indian spice used in Ayurvedic medicine and in some herbal teas.

What does bishop’s weed look like?
There are a few different plants that go by the name bishop’s weed. The Ammi majus variety has dainty white flowers similar to Queen Anne’s lace. A summer bloomer, the plant grows best in full or partial sun during June, July, and August. It attracts bees and other beneficial pollinators.

A Word From Verywell

Self-treating a skin condition with bishop’s weed and avoiding or delaying standard care may have serious consequences. Talk to your doctor if you’re considering the use of bishop’s weed in the treatment of a skin disorder (or any other condition).

An ancient medicinal herb, bishop's weed (Ammi majus) is used to treat skin conditions such as psoriasis and vitiligo.