Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for WILLOW BARK are as follows:
Possibly effective for…
- Treating lower back pain. Willow bark seems to reduce lower back pain. Higher doses seem to be more effective than lower doses. It can take up to a week for significant improvement in symptoms.
Insufficient evidence to rate effectiveness for…
- Joint pain. Research shows that taking a specific product containing glucosamine sulfate, methylsufonlylmethane, white willow bark extract, ginger root concentrate, boswellia extract, turmeric root extract, cayenne, and hyaluronic acid (Instaflex Joint Support, Direct Digital, Charlotte, NC) in three divided doses daily for 8 weeks reduces joint pain. But this product doesn’t seem to help joint stiffness or function.
- Weight loss. Early research suggests that taking willow bark in combination with ephedra and cola nut might cause slight weight loss in overweight and obese people. However, it is not wise to use this combination because of safety concerns about ephedra. Ephedra has been banned in the United States due to severe harmful side effects.
- Osteoarthritis. Research on willow bark extract for osteoarthritis has produced conflicting results. Some research shows it can reduce osteoarthritis pain. In fact, there is some evidence suggesting that willow bark extract works as well as conventional medications for osteoarthritis. But other research shows no benefit.
- Rheumatoid arthritis (RA). Early research suggests that willow bark extract is not effective for rheumatoid arthritis.
- Joint pain.
- Treating fever.
- Other conditions.
More evidence is needed to rate the effectiveness of willow bark for these uses.
- For back pain: Willow bark extract providing 120-240 mg salicin has been used. The higher 240 mg dose might be more effective.
It may cause headaches, stomach upset, and digestive system upset. It can also cause itching, rash, and allergic reactions, particularly in people allergic to aspirin.
Special precautions & warnings:
Pregnancy and breast-feeding: Not enough is known about the safety of using willow bark during pregnancy. It’s best to avoid using it.
Using willow bark while breast-feeding is POSSIBLY UNSAFE. Willow bark contains chemicals that can enter breast milk and have harmful effects on the nursing infant. Don’t use it if you are breast-feeding.
Children: Willow bark is POSSIBLY UNSAFE n children when taken by mouth for viral infections such as colds and flu. There is some concern that, like aspirin, it might increase the risk of developing Reye’s syndrome. Stay on the safe side and don’t use willow bark in children.
Bleeding disorders: Willow bark might increase the risk of bleeding in people with bleeding disorders.
Kidney disease: Willow bark might reduce blood flow through the kidneys, which might lead to kidney failure in certain people. If you have kidney disease, don’t use willow bark.
Sensitivity to aspirin: People with ASTHMA, STOMACH ULCERS, DIABETES, GOUT, HEMOPHILIA, HYPOPROTHROMBINEMIA, or KIDNEY or LIVER DISEASE might be sensitive to aspirin and also willow bark. Using willow bark might cause serious allergic reactions. Avoid use.
Surgery: Willow bark might slow blood clotting. There is a concern it could cause extra bleeding during and after surgery. Stop using willow bark at least 2 weeks before a scheduled surgery.
Interaction with medication
- Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
- Willow bark might slow blood clotting. Taking willow bark along with medications that also slow blood clotting might increase the chances of bruising and bleeding.
Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.
- Willow bark contains chemicals that might increase the amount of acetazolamide in the blood. Taking willow bark along with acetazolamide might increase the effects and side effects of acetazolamide.
- Willow bark contains chemicals similar to aspirin. Taking willow bark along with aspirin might increase the effects and side effects of aspirin.
- Choline Magnesium Trisalicylate (Trilisate)
- Willow bark contains chemicals that are similar to choline magnesium trisalicylate (Trilisate). Taking willow bark along with choline magnesium trisalicylate (Trilisate) might increase the effects and side effects of choline magnesium trisalicylate (Trilisate).
- Salsalate (Disalcid)
- Salsalate (Disalcid) is a type of medicine called a salicylate. It’s similar to aspirin. Willow bark also contains a salicylate similar to aspirin. Taking salsalate (Disalcid) along with willow bark might increase the effects and side effects of salsalate (Disalcid).