Worsening economic times has led to a surge in the use of different parts of medicinal plants in the treatment of various chronic diseases including diabetes mellitus. Objective: Evaluate the histolopathological effects of oral administration of aqueous stem extracts of Costus afer stem on the pancreatic tissue. Methods: Twenty-four wistar albino rats weighing between 132g and 160g were used in this study. Group A served as control and these rats were treated with distilled water. Rats in the groups B, C, and D were treated with 3 different doses of the sample (500mg, 1,000mg and 1500mg/KgBW) respectively. Samples were administered once daily for 14, 28 and 42 days consecutively. Animals were sacrificed 24 hours after the last treatment Results: Results obtained showed that there was distorted pancreatic histoarchitecture at all doses and durations of exposure. Conclusion: Crude stem juice of Costus afer had deletrious effects on the pancreas and such care shoulod be taken in using it amongst the diabetic and general population.