Background & Aim: There is increasing interest in the quest for safe and relatively inexpensive medicines from natural products for the treatment of diabetes mellitus (DM). Thus, the main thrust of this study was to formulate and evaluate the anti-diabetic activity of tablets containing aqueous fraction of Dioscorea dumetorum (bitter yam).Experimental: D. dumetorum was extracted using ethanol followed by aqueous fractionation. A rational amount (200 mg) of the fraction (drug) was blended used to produce seven batches of granules by wet granulation and their micromeritic profiles were determined. The granules were compressed into seven batches of tablets and quality control tests including weight uniformity, crushing strength, friability, drug content, disintegration, and dissolution profiles were undertaken. Anti-diabetic activity of the tablets was assayed using alloxan-induced diabetic rats.Results: Results showed that the granules had good flow properties and compressibility. Tablets produced had good uniformity of weight (0.64 ± 0.01 to 0.66 ± 0.01 g), hardness (4.33 to 8.67 kgf), were less friable (0.05 ± 0.03 to 0.31 ± 0.04 %) with high drug content (98.91 ± 0.55 to 101.39 ± 0.92 %), had acceptable disintegration time (6.44 ± 0.46 to 14.05 ± 0.42 min) for normal release tablets, and recorded 70 – 100 % drug release in 60 min. The result of the anti-diabetic activity study showed that the tablets had blood glucose lowering ability similar to metformin tablet, and therefore could be used as an important alternative in the treatment of diabetes.Recommended applications/industries: Aqueous fractions of D. dumetorum should be further purified and used in the preparation of tablets for the treatment of diabetes mellitus. Extraction and fractionation methods for the plant should be made reproducible for easier industrial application. تفاصيل المقالة