Individuals using herbs such as ginkgo biloba to improve circulation should exercise caution, especially when using prescription medications for heart problems, according to the Cleveland Clinic. Cardiologists warn individuals taking warfarin, diuretics, digoxin or hypoglycemic medications to consult their physicians before taking herbal supplements.
The risk of bleeding increases when patients take ginkgo biloba with blood thinners, and dong quai, ginger, garlic and ginseng can also increase bleeding risks in individuals who do not take heart-related drugs. Many herb-drug interactions occur because anticoagulants called coumarins are natural compounds in the herbs, explains the Cleveland Clinic. The herbal anticoagulants complicate the functions of the prescription drugs. Because herbal product manufacturers do not have to prove their products are safe or effective, the burden is on consumers to be aware.