Many herbal plants have been identified to have antipyretic properties. The current study examines the antipyretic efficacy of acetone, ethanol and methanol extracts of Cajanus Cajan leaves on experimental rats' fevers that were generated by brewer's yeast. We utilised 30 wistar rats, which ranged in weight from 140 to 180g. They were randomly developed into five groups of six rats each. Group one served as the control group and received 5ml/kg of distilled water; group two served as the negative conrrol group and received only brewer's yeast; group three served as the standard group and received 150 mg/kg of paracetamol; and groups four and five served as the test groups and received 200 mg/kg and 400 mg/kg of pigeon pea leaves extract, respectively. All of the test animals received a subcutaneous injection of a 20% w/v suspension of 10ml/kg brewer's yeast to cause fever. Except group one after 18 hours, the rats were given oral doses of paracetamol (standard group, 150 mg/kg) and Cajanus Cajan leaves extract (200 mg/kg, 400 mg/kg) orally. The rats' body temperatures were transrectally measured till 8 hours. Comparing group two (10ml/kg, brewer's yeast) to group three and group four (200mg/kg and 400mg/kg), Cajanus Cajan leaves extract significantly decreased yeast-induced pyrexia. When compared to group two (10ml/kg, brewer yeast), group three (paracetamol, 150mg/kg) similarly shows a sizable decrease. This experiment therefore demonstrates that the antipyretic action of Cajanus cajan leaves extract is dosage dependent and that the effect is brought on by the flavonoid component of the extract. These findings imply that Cajanus Cajan extract has potent antipyretic properties, and that its mechanism may include a reduction in the production of prostaglandins and inflammatory mediators.