In this study, the bioactive compound in Lagenaria breviflora Roberty responsible for its anti-inflammatory and analgesic activities was isolated and chemically characterized.Compounds in the whole fruit, bark, pulp and seed of L. breviflora were partitioned utilizing their various polarity in n-hexane, ethyl acetate, chloroform and ethanol. The fractions of the extract obtained were tested for their bioactivities. The fraction with the most consistent anti-inflammatory and analgesic activities was further purified using accelerated gradient chromatography (AGC) and open column chromatography. Elution of compounds in this fraction was monitored through the different chromatography methods using thin layer chromatography (TLC). The pure compound isolated from the chromatography methods was taken for chemical characterization and elucidation of the structure.Ethyl acetate fraction of the whole fruit exhibited the most consistent anti-inflammatory and analgesic activities out of the 16 fractions obtained. Purification of this fraction with AGC yielded 7 subfractions composing of eluents with similar Rf values on the TLC plate. One of the sub-fractions yielded a compound which was further purified using the open column chromatography method. Eluent obtained from this sub-fraction was renamed YO1.From the result of mass spectroscopy and nuclear magnetic resonance spectroscopy of the compound, the structure of YO1 was determined as a cucurbitacin with 10á-cucurbit-5-ene skeleton (9â-methyl-19-norlanosta 5-ene) backbone structure, with six carbon atoms attached to double bonds and one hydroxyl group.