If you have a severe form of depression or anxiety, I suggest being very cautious about using herbal supplements instead of a mainstream treatment. Talk about this with your doctor.

The research on herbal supplements is, in general, very limited compared to research on standard treatments.

For problems with mood, for example, researchers have been studying St. John's wort (an extract from a plant Hypericum perforatum), SAMe (S-adenosyl-L-methionine), folic acid and omega-3 fatty acids.

Kava and valerian root are names you might hear in connection with anxiety.

Although I think herbal treatments can be a serious option, I urge you not to assume that a treatment is safer or more effective just because it is labeled "natural" or "herbal." If herbal treatments are helpful, it is because they are biologically active. And that means you have to beware of possible negative effects too.

Herbal treatments may seem easier, because you can buy them at a health food store or pharmacy without a doctor’s prescription. But the trade off is that your doctor has less evidence to guide you on important issues such as:

• How effective they are
• What doses are best
• What side effects they have
• How they interact with other medications you might be taking

Also, since these substances are considered dietary supplements, the manufacturer doesn’t have to prove that they are effective for any specific illness. (Prescription and over-the-counter drugs do have to prove this.) And the amount of active ingredient in dietary supplements is likely to vary from product to product. This makes dosing more difficult.

Depending on your situation, your doctor can probably give you advice about major benefits and risks. Your doctor may have limited knowledge about herbal treatments, but should be able to find relevant information to put your decision in context.

The National Institutes of Health also has helpful information about using supplements.