White Willow

Willow bark has been used as a treatment for pain and fever in China since 500 B.C. In Europe, it was primarily used for altogether different purposes, such as stopping vomiting, removing warts, and suppressing sexual desire. However, in 1828, European chemists made a discovery that would bring some of these different uses together. They extracted the substance salicin from white willow, which was soon purified to salicylic acid. Salicylic acid is an effective treatment for pain and fever, but it is also sufficiently irritating to do a good job of burning off warts. Chemists later modified salicylic acid (this time from the herb meadowsweet) to create acetylsalicylic acid, or aspirin.

As interest in natural medicine has grown, many people have begun to turn back to white willow as an alternative to aspirin. One double-blind trial found it effective for back pain; it is also used for other painful conditions such as osteoarthritis, bursitis, dysmenorrhea, headaches, rheumatoid arthritis, and tendinitis. Aspirin and related anti-inflammatory drugs are notorious for irritating or damaging the stomach. However, when taken in standard doses, willow does not appear to produce this same side effect. This may be partly due to the fact that most of the salicylic acid in white willow is present in chemical forms that are only converted to salicylic acid after absorption into the body. In addition, evidence suggests that standard doses of willow bark are the equivalent of 1 baby aspirin daily rather than a full dose. This latter finding raises an interesting question: If willow provides only a small amount of salicylate, how can it work? It appears most likely that other ingredients must play a role as well, such as a substance called tremulacin.

In a 4-week double-blind placebo-controlled study of 210 individuals with back pain, two doses of willow bark extract were compared against placebo. The higher-dose group received extract supplying 240 mg of salicin daily; in this group, 39% were pain free for at least 5 days of the last week of the study. In the lower-dose group (120 mg salicin daily), 21% became pain free. In contrast, only 6% of those given placebo became pain free. Stomach distress did not occur in this study. The only significant side effect seen was an allergic reaction in one participant given willow. Benefits were also seen in a double-blind placebo-controlled trial of 78 individuals with osteoarthritis of the knee or hip.

Standardized willow bark extracts should provide 120 to 240 mg of salicin daily.

Evidence suggests that willow, taken at standard doses, is the equivalent of 50 mg of aspirin, a very small dose. Willow doesn't impair blood coagulation to the same extent as aspirin, and also doesn't appear to significantly irritate the stomach.
Nonetheless, willow could still cause the side effects associated with aspirin such as stomach irritation and even bleeding ulcers if used over the long term. All the other risks of aspirin therapy apply as well. For example, white willow should not be given to children, due to the risk of Reye's syndrome. It should also not be used by people with aspirin allergies, bleeding disorders, ulcers, kidney disease, liver disease, or diabetes, and it may interact adversely with alcohol, \\\"blood thinners,\\\" other anti-inflammatories, methotrexate, metoclopramide, phenytoin, probenecid, spironolactone, and valproate.
Safety in pregnant or nursing women, or those with severe liver or kidney disease has not been established.

If you are taking blood-thinning medications such as Coumadin (warfarin), heparin, Plavix (clopidogrel), Ticlid (ticlopidine), Trental (pentoxifylline), or aspirin; methotrexate; metoclopramide; Dilantin (phenytoin); sulfonamide drugs; spironolactone and other potassium-sparing diuretics; or the antiseizure drug valproic acid: It may be wise to avoid combining white willow with these substances.