Banaba (Lagerstroemia speciosa Pers) leaves has been used as tea or decoction type in the Philippines for blood sugar control and used in the treatment of diabetes in India and contain a treterpenoid compound know as a corosolic acid which can promote the absorption and utilization of glucose in the cell by transporting the stimulated glucose. As such, banaba plays a role in regulating levels of blood sugar and insulin in the blood. Banaba might decrease blood sugar but most of countries prefer to use diabetes medications even though they aware of serious side-effects. Additionally, various adverse effects are reported recently when many diabetic patients have been taken antidiabetic drugs in the long term. Here we reviewed whether banaba and corosolic acid can be replaced for current antidiabetic drugs through published several mechanisms of banaba and antidiabetic drugs, respectively. Consequently, banaba, one of medicinal herbs for antidiabetic effect surely can be functioned and can be a perfect candidate instead of antidiabetic drugs on lowering or maintaining normal blood sugar levels and prevention of diabetic complications without as well as treatment without any adverse effects.