Abstract: The study was undertaken to investigate the possible effect(s) of the hexane extract of the bark of Anacardium occidentale (cashew) and the fractions collected at different stages of the purification process on glucose tolerance in normoglycaemic dogs. The possible hypoglycaemic effect of stigmast-4-en-3-one isolated from the hexane extract of the bark of Anacardium occidentale and cholest-4-en-3-one was also investigated. The hexane extract of the bark of Anacardium occidentale was administered at 300 mg kg-1 Body Weight (BW) to normoglycaemic dogs followed by an oral glucose tolerance test. There was significant reduction in the fasting and postprandial blood glucose concentrations especially at the 1.0 and 2.0 h time points (p<0.05). Subsequent fractions of the hexane extract of the bark of Anacardium occidentale showed a hypoglycaemic effect on fasting and postprandial blood glucose concentrations. A hypoglycaemic assay guided extraction, isolation and structure elucidation produced stigmast-4-en-3-one. Stigmast-4-en-3-one administered at 3 mg kg-1 BW produced significant reductions in the postprandial blood glucose concentrations especially at the 1.5 h time point (p<0.05). Cholest-4-en-3-one at 3 mg kg-1 BW (i.v.) was found to be more potent than stigmast-4-en-3-one at the 1.5 h time point (p<0.05). The results indicate that stigmast-4-en-3-one isolated from hexane extract of the bark of Anacardium occidentale possesses hypoglycaemic activity and this lends credence to the suggested use of this herb in the control and/or management of type 2 diabetes mellitus in Jamaica and other Caribbean islands.