Dental plaque. Early research suggests that applying neem leaf extract gel to the teeth and gums twice daily for 6 weeks might reduce plaque formation. It also might reduce the number of bacteria in the mouth that can cause plaque. However, using a mouth rinse containing neem extract for 2 weeks does not appear to reduce plaque or gingivitis.
Insect repellant. Early research suggests that applying extract of neem root or leaf to the skin helps repels black flies. Also, applying neem oil cream to the skin seems to protect against some types of mosquitos.
Ulcers. Some research suggests that taking 30-60 mg of neem bark extract twice daily by mouth for 10 weeks helps heal stomach and intestinal ulcers.
Psoriasis. Early research suggests that taking neem extract by mouth for 12 weeks, along with daily sun exposure and the application of a coal tar and salicylic acid cream, reduces the severity of psoriasis symptoms in people.