Also don't take echinacea with immune-suppressing drugs, such as cyclosporine, since the herb and drug perform opposite functions.

Patients with autoimmune conditions like lupus, or conditions such as tuberculosis, multiple sclerosis and AIDS, should avoid echinacea.

Patients who are taking MAO inhibitors, primarily use to treat depression, including Nardil and Parnate, should check with their physicians before taking ginkgo.

Also, don't take valerian, or any other sedative herb, with anti-allergy drugs such as Benadryl or Vistaril because the drowsiness that sometimes accompanies antihistamine use may be compounded.

Avoid kava kava if you have a family history of stroke, or are taking medicine for blood pressure, heart disease or diabetes.

Do not mix kava kava with alcohol.

Avoid St. John's Wort when on prescription serotonin-altering antidepressants such as Prozac and Zoloft, MAO inhibitors such as Nardil and Parnate, and the herb kava kava as their effects may increase.

Several British studies warn that people taking anticonvulsants and St. John's Wort should stop taking the herb and contact their physician.  The herb may interfere with the action of these medications, and dosages may need adjustment.

St John's Wort has been found to reduce the effectiveness of birth control pills and HIV treatment medication.

St John's Wort also reduces the effectiveness of the asthma medication theophylline sold under the brand names of Slo-Bid, Theo-Dur, Theolair and Elixophyllin.

Avoid the herb if you are taking any MAO inhibitors because it could result in mania.  Studies also show that the herb may cause irritability if mixed with caffeine.

Don't take Ma huang with diabetes medications because the herb interferes with regulation of blood sugar levels.

Avoid Ma huang when on MAO inhibitors such as Nardil and Parnate because the combination dangerously elevates blood pressure.

Do not take Ma huang with the heart medication Lanoxin because serious disruption of heart rhythm can occur.

Licorice depletes potassium in the body, and severe potassium loss increases the risk of heart rhythm irregularities, especially in patients on the heart medication Lanoxin.  Do not combine licorice with the diuretics Lasix, Hygroten, Lozol or Bumex because potassium loss can be dangerously accelerated.

Licorice can reduce thyroid gland activity so it may alter the required dose of thyroid-stablizing drugs such as Synthroid, Levothroid and levoxyl.

Do not take licorice with blood pressure medications including Adalat, Vasotec and Minizide as the medications' effect could be lessened.

Women who take oral contraception's may be particularly susceptible to high blood pressure, fluid retention, and potassium loss when taking licorice.

It is inadvisable for those with kidney or gallbladder problems or cirrhosis to take licorice.

Men already taking Proscar should avoid saw palmetto, because they act in a similar manner and the combination could result in overdose.

Women taking female hormones for contraception or hormone replacement therapy should not take saw palmetto, as its berries have estrogenic and anti-estrogenic activity.

Do not take psyllium with over-the-counter or prescription laxative medications, as their effects may be increased.

Shown to be effective anti-inflammatory, the oil is also used to alleviate rheumatoid arthritis.  It's used to alleviate PMS, too.

Do not take evening primrose oil with antidepressants such as Wellbutin, as this combination also may increase seizure risk.