Lagerstroemia speciosa leaves are utilized in the Philippines as a folk medicine for the treatment of diabetes and kidney diseases.
In laboratory experiments leaf extracts are reported to stimulate glucose uptake in a dose-dependent manner in similar ways to insulin. Unlike insulin, these extracts do not appear to produce lipid synthesis therefore may be suitable for the treatment of hyperglycemia and obesity resulting from type II diabetes.
The fruit are used India to cure mouth ulcers. The roots are also considered astringent and the seeds narcotic.