Echinacea also should not be used by cancer patients using the chemotherapy drug Methotrexate, as liver toxicity can result. It is strongly advised that AIDS and cancer patients consult with their physician before using this supplement.

When it comes to meteoric rise in popularity in the herbal supplement world, few products can match the now famous supplement, St. John's Wort. St. John's Wort is currently being used by millions worldwide to "chase the blues away," and many say that it has helped them to cope with the debilitating effects of depression, anxiety and even obsessive compulsive behavior. This yellow flowering plant, originally from Europe, flowers in early summer and derives its name from the legendary date that it was originally believed to bloom, June 24th, which is the birth date of John the Baptist.

Commonly taken as an extract, St. John's Wort provides many people relief from depression without the side effects, such as dry mouth and sexual dysfunction that accompany many prescription medications such as Prozac, Zoloft, Tofranil and Elavil. Although this supplement has legions of loyal believers, its value in the treatment of even moderate depression is unclear.

Since depression is a very serious condition that can lead even to suicide, it is not recommended that anyone suffering from depression or anxiety, even in mild cases, look to St. John's Wort as a substitute for medical attention. All treatment for depression should be conducted under the auspices of a medical professional.