Ginger may alter the effects of some prescription and non-prescription medications. If you are currently being treated with any of the following medications, you should not use ginger without first talking to your health care provider.
Blood-thinning medications -- Although ginger may interfere with blood clotting, there have been no scientific or case reports of interactions between ginger and blood-thinning medications, such as aspirin and warfarin. However, people taking medications that thin the blood should use ginger only under the supervision of a health care provider.
Ginger; Zingiber officinale