It's a common belief that anything labeled "herbal" is safe. In fact, many such products can cause adverse effects, either on their own or by interacting with conventional medications prescribed by your doctor.
Research supporting the safety and effectiveness of supplements marketed for relieving arthritis-related pain is scarce. It's especially risky to take supplements if you need surgerysome popular herbs, including ginseng, can reduce the effect of anticoagulant drugs, such as warfarin, making it more likely that you'll develop a blood clot.
Always tell your doctor if you use dietary supplements of any kind.