What Is Bishop's Weed?
Used to treat skin issues, supporting research is lacking
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, California.
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).
What Is Bishop's Weed Used For?
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.
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.
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 healthcare provider 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.
Pre-existing liver conditions may be worsened with the use of bishop's weed, so people with liver problems should speak to their healthcare provider 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.
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 healthcare provider if you're considering the use of bishop's weed in the treatment of a skin disorder (or any other condition).
Is Cannabis Safe During Pregnancy? More Expecting Mothers Are Wondering
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Cannabis and pregnancy; consider it the final taboo. Both are difficult to study: marijuana is still a Schedule 1 drug and has been nationally illegal to use recreationally until very recently, while pregnant and nursing women are often excluded from clinical studies about safe medicine use, over fears of possible harm. Meaning, if you want to know whether any parts of the cannabis plant are safe during pregnancy, you’re not going to find any conclusive answer. In fact, the only thing we do know is that we don’t know how exactly cannabis will affect a woman and her baby.
Yet, despite the lack of long-term clinical studies involving cannabis and pregnancy, marijuana use among women who are carrying or breastfeeding is rising. In California, the number of pregnant women using cannabis almost doubled between 2009 and 2016, according to a study out of Kaiser Permanente Northern California—the only U.S. healthcare system that screens all pregnant women for prenatal marijuana use.
Kelley Bruce, the founder of CannaMommy—a non-profit virtual clinic to educate pregnant, laboring, and postpartum mothers on cannabis—turned to the substance after she was hit by a drunk driver on New Year’s Eve. She’d been living as a children’s ski instructor in Vail, Colorado; with two herniated disks and three months left in the season, Bruce had no choice but to get back on the slopes. So she accepted her doctor’s cocktail of medication: Soma, a muscle relaxer, Percocet for the pain, and Ambien to help her sleep. “I started getting nervous about how I kept needing more [drugs] to feel better,” says Bruce. “And it wasn’t until I had a really scary out of body experience—I was tending to my one-year-old daughter, but couldn’t remember doing it the next day—that I decided I needed to find other options.”
By talking to growers and open-minded doctors alike, Bruce finally found the strain, application, and higher cannabidiol (CBD) to tetrahydrocannabinol (THC) ratio that worked for each specific ailment. (CBD is a compound found in cannabis that is associated with medicinal properties like anti-inflammation and pain relief, and THC is responsible for the plant’s psychotropic effects.) And she told everyone she knew. “I became a walking billboard for medicinal marijuana,” she says. “And that’s when Child Protection Services came knocking on my door.”
Despite displaying her medicinal card, and providing proof that she was working with her doctors, Bruce was charged with endangering a minor and other crimes. “I was completely naive,” says Bruce. “I openly admitted to using a Schedule 1 drug in my home but [thought it was okay because I] never did it in front of my child.” And while most of the charges were eventually dropped after Bruce “rose hell” in the form of countless appeals, letters from the community, past employers, and her daughter’s father, she still got two years of probation. The experience is what led Bruce to start CannaMommy. “Mothers are the most vulnerable cannabis users out there right now,” she says.
Apart from its cultivation practice, CannaMommy is a free, virtual, and confidential clinic designed to help mothers navigate the confusing and expanding world surrounding cannabis and pregnancy. Run by volunteer registered nurses who field clients from California to Germany, most calls are about how to manage symptoms while not harming their babies, as well as understanding the legal ramifications after use, says Marissa Fratoni, RN, the director of wellness for CannaMommy. “One of my patients was recently admitted to the hospital due to hyperemesis gravidarum, or HG,” says Fratoni, explaining that 3% of women experience this severe type of vomiting that leads to dehydration, weight loss, hospitalization, and potential endangerment of the fetus. “She was told she needed IV fluids and a feeding tube in order to stay in her pregnancy. She tried cannabis [instead], and it helped.”
While positive anecdotal evidence is on the rise, the CDC does report that smoking cannabis during pregnancy is linked to lower birth weight in babies. And chemicals from cannabis, particularly THC, can be passed to a baby through a mother’s breast milk. That said, data on the effects of cannabis exposure to the infant through breastfeeding are conflicting. But to limit potential risk to the infant, the CDC recommends breastfeeding mothers reduce or avoid marijuana use altogether.
Cambria Benson, founder of Serra, a “modern druggist” in Portland, Oregon, modified her cannabis use during pregnancy. “Given there is no definitive answer or information when it comes to the safety of cannabis and pregnancy, I only use CBD to deal with extreme nausea or sleep deprivation,” she says, nine months pregnant with her second baby at the time of this interview. “That said, we have plenty of pregnant women who shop [a range of products] at Serra. We don’t judge, because it’s such a personal choice.”
Dr. Janice Knox, MD, MBA, a retired anesthesiologist who now runs a cannabinoid-focused medical practice in Portland with her husband and two daughters, also doctors, believes there is a future in which a low dose of CBD could be seen as a multivitamin, but she still wouldn’t give a blanket okay to using cannabis during pregnancy. “The conversation between the embryo and the mother’s uterus is just too complicated, and there is not enough research to prove efficacy in vivo,” she says, recalling studies that have shown developmental toxicity such as increased embryo-fetal mortality in pregnant rats while under the influence of Epidiolex, the only FDA-approved CBD medication, which has been found to help treat seizures. Knox does believe, however, that one of the best things you can do before a major operation like birth is to mitigate stress.
“It’s the Sphincter Law,” says midwife Laura Erickson, LDEM, CPM, director and owner of Alma Midwifery in Portland, Oregon, recalling the work of renowned midwife Ina May Gaskin (author of such go-to pregnancy books like Spiritual Midwifery and Ina May’s Guide to Childbirth). “In order to give birth, you have to be able to relax.”
Perhaps that’s why there is a sudden movement around CBD and birth, suggests Benson, recalling Serra shoppers who have used cannabis oil vaginally, topically, or orally during delivery. Dr. Andrew Kerklaan, DC, the president and founder of Dr. Kerklaan Therapeutics, a range of hemp-derived, CBD-based topical products, agrees there may be a place for cannabis leading up to and during the recovery period after birth. His topical doesn’t enter the bloodstream, therefore not exposing the baby to the substance. Bruce, ever the pioneer, is getting ready to put out CannaMommy’s first-ever topical made for delivery. Part CBD, THC, olive oil, and vitamin E and D, it’s meant to reduce inflammation, prevent tearing, and help the cervix stretch when applied as the baby’s head starts to crown. “I didn’t even feel the ‘ring of fire’ during my last child’s birth,” says the mother of four. Talk about a positive trip.