Abstract: This review aims to present the information related to chemical composition of Momordica charantia Linn. (Cucurbitaceae), which is used in many Asian countries as a traditional functional food and medicine especially for the treatment of diabetes mellitus. Our main objective was to collect information about active constituents of this plant. Review of literature included PubMed searches with ‘Momordica charantia’, ‘Bitter gourd’ or ‘Bitter melon’ as initial key words. The search was further refined by looking for terms such as ‘Constituents’ (or composition) and ‘Activity’ (or effect) within the results. The earliest report of the chemical screening of M. charantia dates back to 1960. Since then several classes of compounds including cucurbitacins, sterols, alkaloids, proteins and triterpenoids have been isolated. Cucurbitacins are reported to be the main active constituents of M. charantia that have anti-hyperglycemic, anti-hyperlipidemic, hepatoprotective, anti-obesity, anti-cancer and anti-viral activities. The M. charantia is a rich source of chemically novel compounds and needs elaborate screening strategies to dwell into the pharmacological effects of its phyto-constituents at the molecular level.