Devil’s Claw has been associated with documented reports of potential interactions with warfarin.

– Am J Health Syst Pharm 2000 Jul 1;57(13):1221-7; quiz 1228-30 —
Potential interactions between alternative therapies and warfarin. — Heck AM, DeWitt BA, Lukes AL.

Should thus not be used in patients on oral anticoagulant and/or antiplatelet therapy.

– Ann Ital Med Int 2000 Apr-Jun;15(2):139-43 — [Oral anticoagulants and medicinal plants. An emerging interaction] — Argento A, Tiraferri E, Marzaloni M.

Avoid during pregnancy.

Mild gastrointestinal distress at higher dosages.
– Newall CA, Anderson LA, Phillipson JD. Herbal Medicines: A guide for Health-care Professionals.London: The Pharmaceutical Press, 1996:296.26.

Devil’s Claw should not be taken by anyone with stomach or duodenal ulcers. Those with gallstones should consult their doctor first. Mild stomach upsets occasionally occur.