This study was designed to investigate the scientific basis for the use of Acacia nilotica
root extract for treatment of fever and pain in traditional medical practice. Anti-Pyretic study was carried out using Brewer’s yeast suspension to induce pyrexia. The hot plate, tail immersion and acetic acid-induced writhing tests were the nociceptive models used for analgesic study. Anti-pyretic and analgesic activity of the extract was compared with acetaminophen that was used as control drug. Five groups comprising five animals per group were used for each study. Group 1 was administered 10 ml/kg body weight of distilled water, Group 2 was administered 150 mg/kg body weight of acetaminophen while groups 3, 4 and 5 were administered 100, 200 and 400 mg/kg body weight of extract respectively as single oral dose. The extract produced significant dose-dependent reduction in rectal temperature of rats at 200 and 400 mg/kg body weight. Significant analgesic activities were also observed in the hot plate, tail immersion and acetic acid induced writhing, after administration of 200 and 400 mg/kg b.w of extract which is comparable to the control drug, acetaminophen. The results from this study showed that aqueous extract of Acacia nilotica
root at 200 and 400 mg/kg body weight possess significant antipyretic and analgesic activities. This provides scientific support for its traditional medical use in the treatment of fever and pain.