Bitter melon is a tropical vine found extensively throughout the Caribbean, Africa, China, India and Southeast Asia. The leaves are dried and encapsulated, or steeped in hot water to prepare a tea, which is a traditional treatment for malaria, hypertension, asthma, gastrointestinal disorders and diabetes. While the herb does demonstrate many beneficial properties, there are also a few potentially harmful effects associated with bitter melon.
A monograph created by Natural Standard and published online, in part, by Aetna InteliHealth Inc., states that you should avoid bitter melon preparations if you have a known allergy to gourds and melons belonging to the Cucurbitaceae family of plants, such as cantaloupe and honeydew.
According to information provided by Drugs.com, the plant contains vicine, charantin and an agent referred to as polypeptide P, all of which have been shown to lower blood sugar levels in diabetic mice as well as reduce insulin resistance. While these observations may support the historical use of bitter melon leaves to treat diabetes, the use of this herb may actually produce negative effects if you take medications to regulate your blood sugar. Whether you have diabetes type I or type II, please talk to your doctor before self-treating your condition with this herb.
Although this herb is a traditional remedy for gastrointestinal problems, researchers have found that the ingestion of bitter melon extract may produce ulcers. In fact, the results of a study published in the Jan. 29, 2010 issue of "Indian Journal of Gastroenterology" reported that bitter melon extracts also lead to hematemesis, the medical term for the vomiting of blood.
Drugs.com says that a protein present in the bitter melon plant appears to exert antifertility activity in male rats and in female mice.
Drugs.com also states that mormordicine alkaloids present in the bitter melon plant, collectively referred to as momorcharins, increase the risk of spontaneous abortion. Do not take liquid extracts or drink tea made from bitter melon leaves during pregnancy. Since it is not known if these agents pass through breast milk, women should also avoid using this herb while nursing.
The Natural Standard monograph notes that two cases involving children have been reported in which drinking bitter melon tea caused blood sugar levels to fall dramatically, resulting in coma.
The National Standard monograph also states that bitter melon may interfere with the absorption or escalate the effects of several supplements and medications, including diabetes drugs, anthelmintics to treat parasitic infections, chemotherapy medications and antiviral drugs used in the treatment of HIV/AIDS.