Does anyone know of a drug interaction checker that checks herbal supplements also?

Several: There are now several online databases that include herbs when checking for drug interactions. However, not all possible interactions are known. A good place to start is http://www.Mayoclinic.Com/health/drug-information/drugherbindex another useful resource is http://www.Drugs.Com/drug_interactions.Html which, while more focused on drug-drug interactions includes many herbs in its database.

The medscape site: Is reasonable, and can be found at: http://reference.medscape.com/drug-interactionchecker But realize, particularly when it comes to herbals(in general, all nutraceuticals) there is relatively limited information about all the interactions because they are just not studies as in depth as the FDA regulated chemicals.