In a recent article by Holden and colleagues, echinacea and other herbs are identified as dangerous for patients taking arthritis drugs.¹ Is there evidence to support this claim?

The article states that devil’s claw, ginkgo, and garlic may have antiplatelet or anticoagulant effects, potentially exacerbating the risk of gastrointestinal bleeding from non-steroidal anti-inflammatory drugs or corticosteroids. No direct evidence supports these claims. A review of the references indicates that only one is based on an actual case report, a rare and unusual event of excessive garlic ingestion causing a spontaneous spinal epidural haematoma, which would not be considered typical. The other references are experimental studies or theoretical discussions.

Another questionable claim is that arthritic patients are at an increased risk of hepatotoxicity from the use of echinacea. Referenced is an article by Miller² stating: “If used beyond 8 weeks, echinacea could cause hepatotoxicity and therefore should not be used with other known hepatotoxic drugs, such as anabolic steroids, amiodarone, methotrexate, and ketoconazole”. This is unsubstantiated as no studies or case reports of hepatotoxicity caused by echinacea have been published. Furthermore, Miller comments that “echinacea lacks the 1,2-unsaturated necine ring associated with hepatotoxicity of pyrrolizidine alkaloids”, confirming that echinacea is not hepatotoxic. Moreover, Holden and colleagues fail to report that Fugh-Berman immediately contested the suggestion that echinacea might be hepatotoxic.³

A review of the safety of echinacea demonstrates …