The aim of the study was to evaluate the in vivo cytotoxic and analgesic activities of methanol extract of leaves of Persicariacapitata. The cytotoxic bioassay was evaluated using brine shrimp (Artemiasalina Leach) lethality test where the LC50 value for the extract was found to be 12.31 µg/ml where the LC50 value for the standard potassium dichromate was 31.26 µg/ml. The extract showed significant writhing inhibition in acetic acid induced Swiss Albino mice at doses of 250 and 500 mg/kg body weight and percentage (%) of inhibition was 58.66% and 62.36% respectively compared to the standard diclofenac at a dose of 10 mg/kg body weight. The overall result obtained from the study suggests the cytotoxic and analgesic properties of leaves of the plant. The effect of both cytotoxic and analgesic of the methanol extract was significant.