Neem has anti pyretic (fever reducing) compounds that have traditionally been used to reduce fevers. Studies have known that Nembutal to be anti pyretic while nimbi reduces the secondary rise in fever.
In a study to determine the effectiveness of nimbidin (a crude extract of neem leaves) as a fever reducer the results were striking. The study required that fevers be induced in rats with a vaccine. Those that developed at least a two-degree increase in body temperature were selected for the study. Basically, one-third of the rats were given water, one-third were given 500 mg of aspirin while one-third were given 100 mg of nimbidin. Those that received the aspirin began to see the fever go down after two hours by about one degree then slowly rise. Those given nimbidin had their temperature go down by about one degree after one hour, two degrees after two hours then rise by about half a degree after three hours and stabilize.
To reduce fevers in adults drink two cups of neem leaf tea made with five neem leaves each. Repeat, if needed, after four hours. Since some of the compounds in neem resemble those found in aspirin, neem is not recommended at this time for use by small children for fever reduction.