The neem tree is provides probably the most versatile herbal healing materials in Ayurveda, next to honey, ghee, and garlic. It's used for everything from allergies to birth control.
Neem may be of some value to type 2 diabetics who can't get their blood sugar levels under control. Some research suggests that the anti-inflammatory action of neem may protect the insulin-producing beta cells of the pancreas from the series of events that causes them to "burn out." Much better, however, is to keep blood sugar levels under control!
Gupta S, Kataria M, Gupta PK, Murganandan S, Yashroy RC. Protective role of extracts of neem seeds in diabetes caused by streptozotocin in rats. J Ethnopharmacol. 2004 Feb;90(2-3):185-9.