Bean pods (Phaseolus vulgaris) are among the most widely used traditional remedies against diabetes mellitus. Historical knowledge is summarized and compared to recent study results. Reports dating from the first half of the $20^{th}$ century as well as recent publications show contradictory results. It seems that Phaseolus preparations should not be considered the first choice in phytopharmaceutical treatment of diabetes or lead structure research. To be effective, fairly high doses of aqueous extracts need to be given. Because of their fiber content and an ${alpha}$-amylase inhibitory effect, beans might be more useful as food components in preventing or ameliorating type 2 diabetes.