Because willow bark contains salicylates, it has the potential to interact with a number of drugs and herbs. Talk to your doctor before taking willow bark if you take any other medications, herbs, or supplements.

Willow bark may interact with any of the following:

Anticoagulants (blood-thinning medications) -- Willow bark may strengthen the effects of drugs and herbs with blood-thinning properties.

Beta blockers -- including Atenolol (Tenormin), Metoprolol (Lopressor, Toprol-XL), Propranolol (Inderal, Inderal LA). Willow bark may reduce the effectiveness of these drugs.

Diuretics (water pills) -- Willow bark may reduce the effectiveness of these drugs.

Nonsteroidal anti-inflammatory drugs -- including ibuprofen (Advil, Motrin) and naproxen (Aleve). Taking willow bark with these drugs may increase risk of stomach bleeding.

Methotrexate and phenytoin (Dilantin) -- Willow may increase levels of these drugs in the body, resulting in toxic levels.