Finasteride (Proscar) -- Because saw palmetto may work similarly to finasteride (Proscar), you should not use this herb in combination with finasteride or other medications used to treat BPH.

Antiplatelet and anticoagulant drugs (blood-thinners) -- Saw palmetto may affect the blood's ability to clot, and could interfere with any blood-thinning drugs you are taking, including:

• Warfarin (Coumadin)
• Clopidogrel (Plavix)
• Aspirin

Oral contraceptives -- Because saw palmetto may have hormone-like effects, it may make oral contraceptives less effective, raising the risk of unplanned pregnancy.