In modern Europe, devil's claw is used to treat all types of joint pain, including osteoarthritis, rheumatoid arthritis, and gout. Devil's claw is also used for soft tissue (muscle-related or tendon-related) pain.

Like other bitter herbs, devil's claw is said to improve appetite and relieve mild stomach upset.

What Is the Scientific Evidence for Devil's Claw?

The evidence for devil's claw is fairly preliminary, with the largest and most well-designed studies showing marginal benefits at best. Most studies have evaluated it for treatment of arthritis.

A double-blind study compared devil's claw to the European drug diacerhein.¹ Diacerhein is a member of a drug category not recognized in the United States: the so-called "slow-acting drugs for osteoarthritis" (SADOAs). Unlike anti-inflammatory drugs such as ibuprofen, SADOAs do not give immediate relief, but rather act over a period of weeks to gradually reduce arthritis pain. The supplements glucosamine and chondroitin have been proposed as natural SADOAs.

In this trial, 122 individuals with osteoarthritis of the hip and/or knee were given either devil's claw or diacerhein for a period of 4 months. The results showed that devil's claw was as effective as diacerhein, as measured by pain levels, mobility, and need for pain-relief medications (such as acetaminophen or ibuprofen). While this might seem impressive, diacerhein itself is only slightly effective,¹² and, in such cases, comparative studies must use a placebo group to achieve reliable results.

Another double-blind study followed 89 individuals with rheumatoid arthritis for a 2-month period. The group given devil's claw showed a significant decrease in pain intensity and improved mobility.²A third double-blind study of 50 people with various types of arthritis found that 10 days of treatment with devil's claw provided significant pain relief.³A fourth study compared devil's claw against Vioxx, an anti-inflammatory drug (currently off the market).¹³ While it was widely reported that devil's claw was equally effective as the drug, in fact, the study was too small to produce statistically meaningful results.

Other studies have evaluated devil's claw for treatment of muscular tension and discomfort. One of these was a 4-week, double-blind, placebo-controlled trial that evaluated 63 patients with muscular tension or pain in the back, shoulder, and neck.¹¹ The results showed significant pain reduction in the treatment group as compared to the placebo group. However, a double-blind study of 197 individuals with back painfound devil's claw marginally effective at best.⁴Similarly unimpressive results were seen in a previous double-blind study of 118 people with back pain.⁵

We do not know how devil's claw might work. Some studies have found an anti-inflammatory effect, but others have not.^6,7Apparently, the herb does not produce the same changes in prostaglandins as standard anti-inflammatory drugs.⁸

Dosage

A typical dosage of devil's claw is 750 mg 3 times daily of a preparation standardized to contain 3% iridoid glycosides.

Safety Issues

Devil's claw appears to be safe, at least for short-term use. In one study, no evidence of toxicity emerged at doses many times higher than recommended.⁹In a review of 28 clinical trials dating back 20 years, researchers found no instances where adverse effects were more common than those associated with a placebo. Minor adverse effects, most gastrointestinal in nature, occurred in roughly 3% of patients.¹⁴

Devil's claw is not recommended for people with ulcers. A 6-month open study of 630 people with arthritis showed no side effects other than occasional mild gastrointestinal distress. According to one case report, the herb devil's claw might increase the potential for bleeding while taking warfarin.¹⁰

Safety in young children, pregnant or nursing women, or those with severe liver or kidney disease has not been established.

Interactions You Should Know About

If you are taking:

• Blood-thinning medications such as warfarin (Coumadin) or heparin: Devil's claw might enhance their effect, possibly producing a risk of bleeding.