Neem bark is a common ingredient in traditional medicine throughout India and southeast Asia. The neem tree is a large evergreen tree that grows in tropical and subtropical climates in India, southeast Asia, the Middle East, and eastern Africa. The bark of the neem tree is dried, ground into a powder, and used as a topical or oral medicine for a wide variety of ailments. While clinical data on the effectiveness of neem bark is lacking, preliminary trials show tentative support for traditional claims of the bark's antibacterial, anti-fungal, insecticidal, and spermicidal properties. Neem bark extract is a popular component of alternative medicine systems across the world.
The neem tree is considered to have powerful healing properties in traditional Indian medicine. The powdered bark is used to treat ailments including fever, leprosy, chicken pox, skin diseases, parasites, indigestion, and malaria. It is applied to the skin as an insect repellent, and is used to keep harmful insects away from gardens and crops. It has been used topically as a form of contraceptive and orally to terminate pregnancies. The twigs of the neem tree are commonly chewed as a form of oral hygiene, based on the strength of the bark's antibacterial properties.
Neem bark's effectiveness as an insect repellent and topical fungicidal agent has shown promise in testing, although much of the research has focused on the more potent seeds and oil of the neem tree. While the powdered bark has been shown to have measurable spermicidal properties, it has not been proven as an effective contraceptive. The powdered bark does appear to be an effective astringent and anti-inflammatory compound. Preliminary testing has shown some promise in the use of compounds present in neem bark for fighting certain forms of cancer. Despite neem's overall popularity as an herbal supplement and alternative medicine, the lack of clinical data has largely excluded it from mainstream Western medical practices.
The active compounds in neem bark appear to be safe for human consumption in moderate doses. Human and animal testing has revealed no significant side effects when consuming doses of the bark up to 0.078 ounces per pound of body weight (9 grams per kilogram). It is possible to fatally overdose on neem bark extract, however, but the specific lethal dose is not known. In addition, the bark has the potential to negatively interact with a wide range of medications. Due to these concerns, neem bark has not been recommended for use by pregnant women and children.
