Different genera of Menispermaceae are being used by herbal manufacturers in formulations of the drug Patha. The important sources of Patha are roots of Cissampelos pareira Var. hirsuta, Cyclea peltata and Stephania japonica, and these genera are being used to treat ailments associated with pyrexia in Ayurvedic system of medicine. The objective of the present study was to evaluate the antipyretic effects of the methanol extracts of roots of above said plants using Yeast induced pyrexia in albino rats. Rectal temperatures were recorded before and after inducing pyrexia at interval of one hour for five hours. At the same time parallel experiments were run with a standard antipyretic (paracetamol) and the vehicle (1% Tween 80). Methanol extract of Cissampelos pareira Var. hirsute at dose of 200mg/kg body wt. showed significant antipyretic activity.