Coumarins are molecules varying from simple to more complex compounds that are widely available in nature, while some of them have been synthesized. They possess significant pharmacological potential, but until now their applicability in medicine has been limited to their ability to limit coagulation in blood. Our immune system plays a major role in disease states, with both ends of the spectrum being significant. Both a slow or absent immune reaction on one hand and an overreaction of the system on the other hand may be detrimental to our health. Since the process of coagulation seems to be related to the immune system, studies showing a possible role for coumarins and their lead compounds in modulating the immune system. were searched for in databases like PubMed, Google Scholar and Hinari. Several studies with promising results revealing a role for coumarins in modulating the immune response, were found However, all these studies have been carried out in in vitro and simple animal models. Randomized clinical trials will be required to demonstrate the therapeutic value of these readily available coumarin compounds.