The Health Benefits of Bishop’s Weed
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.
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.”
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Bishop’s weed (Ammi majus) is a common garden plant sometimes used in herbal medicine. It’s sometimes referred to as lace flower, bishop’s flower, or lady’s lace. Bishop’s weed is most often used in the treatment of skin disorders.
The term bishop’s weed refers to several similar plants. Ammi majus should not be confused with Trachyspermum ammi, also called ajwan or carom, which is used in Ayurvedic medicine, or Ammi visnaga, commonly referred to as khella.
Despite bishop’s weed’s purported health benefits, there is limited scientific evidence to support its medical use.
Bishop’s weed has been used to treat health conditions dating back to 2000 B.C.E. in Egypt. However, there is a lack of modern research to support these health claims.
A number of studies published in the mid-20th century suggest that bishop’s weed may aid in the treatment of vitiligo, but more recent research on bishop’s weed’s health effects is lacking.
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 topically (i.e., 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 light exposure.
In a medical procedure known as PUVA therapy (which stands for “psoralen-UVA therapy”), patients receive methoxsalen and are then exposed 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.
A preliminary study on bishop’s weed published in Organic and Medicinal Chemistry Letters in 2012 found that certain compounds in bishop’s weed may help reduce inflammation and fight off viruses.
More research is needed to determine whether bishop’s weed can be recommended in the treatment of any health condition.
Selection, Preparation & Storage
There isn’t enough scientific evidence to support the use of bishop’s weed for any health issues, so there is no recommended dose. Follow the instructions on the label and speak to your healthcare provider.
When purchasing bishop’s weed, check the label for its scientific name, Ammi majus. Do not confuse it with the spice ajwain (carom), which is from the plant Trachyspermum ammi, or khella, which comes from the plant Ammi visnaga.
Supplements haven’t been tested for safety and dietary supplements are largely unregulated. In some cases, the product may deliver doses that differ from the specified amount for each herb. In other cases, the product may be contaminated with other substances such as metals.
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 long-term or regular use of this herb. However, there’s some concern that bishop’s weed may trigger such side effects as headache, nausea, and vomiting.
Since bishop’s weed changes the way your skin cells react to exposure to ultraviolet light, bishop’s weed may increase sensitivity to the sun and, in turn, raise your risk of skin cancer. Additionally, bishop’s weed may cause liver conditions to worsen, as well as inhibit blood clotting.
People who are 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.
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.
Bishop’s weed may slow blood clotting and should not be taken along with other medications that slow clotting, including aspirin, Plavix (clopidogrel), diclofenac, ibuprofen (Advil, Motrin, etc.), naproxen (Naprosyn, Aleve, etc), Lovenox (enoxaparin), Coumadin (warfarin), and heparin, among others.
The safety of supplements in pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications has not been established.
Is bishop’s weed a spice?
Ammi majus, commonly known as bishop’s weed, is not a spice. However, another plant also called bishop’s weed, Trachyspermum ammi, is the Indian spice known as ajwain or carom. Ajwain is used in Ayurvedic medicine and can be found as an ingredient in herbal teas.
Can you use bishop’s weed treat vitiligo?
Bishop’s weed has been used as a folk remedy to treat vitiligo by making a tea, mixing with 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. The plant contains psoralens, substances that react with ultraviolet (UV) light to darken skin, but doing so can result in phytophotodermatitis, a painful skin reaction that results in blisters and scarring 24 to 48 hours after exposure.
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.
Scientific Name(s): Trachyspermum ammi L. Sprague.
Common Name(s): Ajava seeds, Ajowan caraway, Ajowan seed, Ajowanj, Ajwain, Bishop’s weed, Carum, Omum., Yavani
Medically reviewed by Drugs.com. Last updated on Dec 30, 2019.
High quality clinical trials are very limited. The medical literature documents numerous pharmacological activities including analgesia (neuropathic), antifungal, antimicrobial, hypolipidemic, antihypertensive, antilithiasis, abortifacient, antitussive, nematicidal, anthelmintic, and antifilarial.
Bishop’s weed is commercially available as a single entity or herbal blend in numerous dosage forms including capsules, liquids, powders, and cream. Internet sources list the product as being primarily marketed as “ajwain” and as an overall panacea. One herbal blend prescribes 1 or 2 capsules (200 mg/capsule) with a full glass of water for GI discomfort. The prescription drug methoxsalen, as documented by various Internet resources, was developed from bishop’s weed (Ammi majus Linn) and is used to treat several skin conditions. Use of a 10% topical cream twice daily has been supported by a clinical trial in adults with neuropathic pain.
Hypersensitivity to any of the components of bishop’s weed. Avoid use during pregnancy and lactation due to documented adverse effects.
Avoid use. Documented adverse effects. Bishop’s weed was listed as 1 of 14 indigenous medicinal plants used for abortion in some districts of India in 1987, and it may also cause congenital defects. The same review article also documents a risk of human fetotoxicity as observed in rat teratogenicity studies.
Data are lacking concerning specific drug interactions. Potentiation of the effects of antibiotics and antiplatelet medications could be theorized.
Caution may be warranted in patients taking nonsteroidal anti-inflammatory drugs (NSAIDs) or antiplatelet medications due to platelet aggregation inhibition by bishop’s weed.
Bishop’s weed is toxic in high doses and can result in fatal poisoning. Avoid use during pregnancy due to documented adverse effects.
- Apiaceae (carrot)
Bishop’s weed is a smooth, or slightly hairy, branched annual growing 60 to 90 cm tall. The stem is striated, containing up to 16 small, white flowers, and the leaves are pinnately divided with a terminal and 7 pairs of adjacent leaflets. The grayish-brown, ovoid, aromatic fruit is 2 mm long and 1.7 mm wide. The fruit is harvested from February to March and is separated when dried. The plant is indigenous to India, Iran, Egypt, Afghanistan, and Ethiopia. It is widely grown in arid and semiarid areas, particularly where the soil contains high levels of salt.1, 2, 3 The scientific name is synonymous with Carum copticum (L.) Benth., Ammi copticum L. and Hook. f. and Trachyspermum copticum (L.) Link.1
Bishop’s weed has been used for curing numerous diseases in humans and animals,2 and it is used in Ayurvedic and Unani medical systems.4, 5, 6, 7 Ayurvedic use of bishop’s weed includes treatment of atrophy, cachexia, spasms, and rheumatism. Patients diagnosed with fever and lung ailments, including bronchitis, the common cold, cough, consumption, and emphysema have also benefited from treatment with bishop’s weed. To treat asthma, a paste of crushed fruit is applied on the chest. The paste is also used for colic. Bishop’s weed may be helpful in treating several GI disorders, including diarrhea, gastrosis, atonic dyspepsia, cholera, flatulence, and indigestion. In the Unani system, the plant is used to enhance the body’s immune system.2, 5 The fruit has stimulant, antispasmodic, and carminative properties.6 The plant has also been used to treat abdominal tumors and hemorrhoids.2 The seeds are bitter and pungent, and have carminative and laxative properties. They have been used in folk medicine to remove systemic helminth infections in humans and domestic animals.8
Traditionally, bishop’s weed has been used as a spice and as a preservative. It is used as a commercial product in the food and flavoring industries.9 The fruits are used to flavor curries, pickles, biscuits, confections, and beverages.10, 11 The plant is used in soaps and perfumes and has several applications in aromatherapy dating to ancient times.4, 12 Ajwain oil, which is found in the seeds, is used in India as an antiseptic to treat nasal catarrh and as an antifungal for skin diseases. It is also used as a mouthwash, gargle, or toothpaste preparation in dentistry. Bishop’s weed has been used as an insecticide and anthelmintic.4 The plant has been made into solutions, ointments, lotions, powders, and deodorants.
The seeds of bishop’s weed contain 2% to 4.4% brownish-colored oil, which is known as ajwain oil.2 The major constituent of the oil is thymol (35% to 60%).13 It crystallizes easily and is sold in India as “flowers of Ajowan.”4 The seeds also contain fiber (11.9%), carbohydrates (38.6%), tannins, glycosides, moisture (8.9%), protein (15.4%), fat (18.1%), saponins, flavone, and mineral matter (7.1%) containing calcium, phosphorous, iron, and nicotinic acid.2, 13 The nonthymol fraction (thymene) contains para-cymene, gamma-terpenine, alpha- and beta-pinenes, dipentene, alpha-terpinene, and carvacrol.4 Minute amounts of caphene, myrcene, and alpha-3-carene also have been found in the plant. Alcoholic extracts contain a highly hygroscopic saponin. From the fruits, a yellow, crystalline flavone and a steroid-like substance have been isolated.
The seeds also contain 6-O-beta-glucopyranosyloxythymol, a glucoside.10 Several other chemical studies have reported 69% carvacrol in bishop’s weed14 and a yield of 25% oleoresin containing 12% volatile oil (thymol, gamma-terpinene, para-cymene, and alpha- and beta-pinene).10 The principal oil constituents of bishop’s weed are carvone (46%), limonene (38%), and dillapiole (9%).15 The essential oil obtained by steam distillation of the fruits of Trachyspermum copticum yielded thymol (61%), para-cymene (15%), and gamma-terpinene (12%).16
Uses and Pharmacology
Clinical studies are limited. However, the medical literature documents numerous pharmacological activities for bishop’s weed including antifungal,17 antimicrobial,18 hypolipidemic,2 antihypertensive,19, 20 antilithiasis,21 abortifacient,2 antitussive,22 nematicidal,23, 24 anthelmintic,2 and antifilarial.2
In a double-blind, randomized, placebo-controlled trial (n=92), the effect of topical T. ammi 10% cream on neuropathic pain was investigated in adults with moderate to severe neuropathic pain. Burning feet was the main complaint and diagnoses included diabetic neuropathy, postsurgical or posttraumatic neuropathic pain, or neuropathic pain for at least 6 months. The essential oil of Ajwain seeds was extracted and compounded into a 10% cream that was applied twice daily for 28 days. The mean changes in absolute pain scores for feet burning (−3.55 vs −0.76), numbness (−0.58 vs −0.11), allodynia (−0.64 vs −0.06), and tingling (−1.69 vs −0.16) were all significantly greater in the Ajwain group versus placebo, respectively (P Unknown
Learn about the potential benefits of Bishop’s Weed including contraindications, adverse reactions, toxicology, pharmacology and historical usage.