The safety and efficacy of Trigonella foenum-graecum extract was investigated using 20 male volunteers aged 20-30 years. They were randomly treated with either 40 mg/kg aqueous extract powder in 10 mL distilled water or 10 mL distilled water in which coffee simulated the extract. The extract significantly lowered blood glucose level by 13.4% 4 hours after ingestion. A significant change of 14.1% was observed in potassium levels. No significant alteration in serum cholesterol, total serum protein and blood urea occurred. Approximately one-third experienced feelings of hunger, frequency of micturition or dizziness during the 24 hours after ingestion. The aqueous extract effectively reduced blood glucose in normal subjects safely. Its hypokalaemic effect merits further investigation.