Diabetes is on the rise, and has become a major public health issue. In view of limitations of available glucose lowering therapy, there is a need to explore and develop natural remedies with anti-diabetic properties. Spices such as cinnamon, cloves, bay leaves, and turmeric display insulin-enhancing activity in vitro. Cinnamon or Dalchini is popularly use as a spice for its fragrance and flavour in wide variety of traditional foods. Among various types of cinnamon, C. zeylanicum is well known as effective substitute for diabetes. Cinnamaldehyde is one of the major constituents (65-80%) of bark oil extracted from C. Zeylonicum which seems to reduce plasma blood glucose concentration more effectively when it is compared with metformin. It enhances the expression of proteins involved in glucose transport, insulin signalling, and regulates dyslipidaemia. This review describes the basic and clinical pharmacology of cinnamon.