Dr. Darrell Hulisz from Case Western Reserve University School of Medicine in Cleveland, Ohio reviews popular herbals.

Let’s focus on safety issues.


  • Common side effects include unpleasant taste and allergic reactions.
  • Because the flower is related to ragweed, cross allergenicity may occur in people allergic to ragweed.
  • Not recommended in patients with progressive or autoimmune disorders.


  • Might lower blood pressure in people with hypertension.
  • Use cautiously in people with bleeding disorders or in those taking antiplatelet therapy.
  • Monitor for deceased blood levels of warfarin (Coumadin).
  • Malodorous breath and garlic-like body odor.

Ginkgo biloba

  • Mild gastrointestinal side effects and headache.
  • Avoid in patients using anticoagulants (eg, warfarin; Coumadin) or antiplatelet therapy (eg, aspirin or clopidogrel [Plavix]), or in those with active bleeding such as peptic ulcer disease.
  • Not recommended in patients with seizure disorders.

St. John’s wort

  • Should not be taken with serotonin uptake inhibitors (SSRIs), as symptoms of serotonin syndrome might occur (headache, sweating, dizziness, and agitation)
  • Avoid during pregnancy.
  • Associated with photosensitivity.
  • Can reduce blood levels of digoxin (Lanoxin) and indinavir (Crixivan).
  • Cases of heart transplant rejection were associated with a reduction in cyclosporine (Sandimmune) blood levels.
  • Breakthrough bleeding and unwanted pregnancies reported in women who also took oral contraceptives.


  • Restlessness and palpitations.
  • Additive effect with other central nervous system depressants.
  • Caution if operating machinery when starting treatment.
  • Headaches, excitability, and uneasiness.


  • Allergic reaction.
  • Sedative effects — use with caution when taking drugs with sedative side effects, or with alcohol.


  • Prolonged bleeding
  • Caution in people taking anticoagulants.
  • Mild gastrointestinal upset, including heartburn, diarrhea, and mouth irritation.


  • Avoid in people with heart disease who take other stimulants.
  • Rarely associated with reversible breast pain and tenderness, and postmenopausal bleeding.
  • Overuse associated with diarrhea, hypertension, nervousness, dermatologic eruptions, and insomnia.
  • Don’t use in people with active bleeding.
  • Use cautiously with anticoagulants and/or antiplatelet medications.

Saw Palmetto

  • Headache and intestinal upset.

Black cohosh

  • Rash or intestinal upset.
  • Don’t use in lactating or pregnant women.
  • Avoid in women with a history of estrogen-dependent tumors or endometrial cancer.

The bottom line?
Many of the side effects listed here are supported by limited data. Check with the article for more details and guidelines.

11/25/08 22:22 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at www.Vicus.com, a complementary and alternative medicine website.