Morinda citrifolia Linn (Rubiaceae) is commonly known as Noni and grows widely throughout the Pacific. It has been reported to have a broad range of therapeutic and nutritional value. The presently available drugs provide only symptomatic relief and are not free from side effects. Main objectives of this research work were to evaluate the analgesic effect of the stem bark of Morinda citrifolia in various animal models. The methanolic extract of stem bark has reduced pain in tail flick, tail clip and tail immersion analgesic models. The extract has also reduced number of writhings in acetic acid induced writhing model. The study revealed that the methanolic extract of stem bark at the dose level of 50, 100, and 200 mg/kg body weight significantly produced antinociceptive, effect which may be due to blockade or release of endogenous substances that stimulate pain nerve endings similar to aspirin and other NSAIDs.
