Hyacinth bean (Lablab purpureus), known as bian dou (扁豆) in traditional Chinese medicine (TCM), has a long history of use in East Asia as a food and medicinal herb. In TCM, it is considered to have properties that strengthen the Spleen, which is associated with digestion and energy production in TCM theory. Hyacinth bean is often used to treat symptoms such as poor appetite, loose stools, diarrhea, and fatigue—conditions attributed to "Spleen deficiency" in TCM terminology. The beans are typically stir-fried or processed in herbal formulas for these purposes.

The traditional use is documented in multiple classic Chinese materia medica texts, where it is described as being sweet and neutral in nature, mainly entering the Spleen and Stomach meridians. However, there is very limited modern scientific research directly validating these TCM claims or elucidating the mechanisms by which hyacinth bean may support digestive health or "Spleen" function in biomedical terms. Some studies have investigated its nutritional content and antioxidant properties, but these do not specifically establish efficacy for supporting the Spleen as defined in TCM or in Western medicine.

In summary, the use of hyacinth bean to support the Spleen system is justified primarily by traditional usage, with minimal scientific validation available to date.