Three-fourths of the women in America experience hot flashes during menopause and they continue for five years or longer.

So, a study involving Chinese herbs was conducted to see if it would help.

The study itself was a struggle. Doctors say they found it difficult to get other patients to stop their herbal treatments in order to be in the study.

The other problem was product consistency. NIH researchers say herbal supplements used in their studies don't have the same potency from one year to the next, even if reputable companies produce them. That makes the study results impossible to measure over time.

As a result, there's not much solid scientific information about herbal supplements and menopause available yet.

But, one of the most popular alternatives for fighting hot flashes is soy. Soybeans contain Phyto-Estrogens, or plant estrogens, which behave like weak forms of your body's own estrogen. Some studies have shown it can help. Other studies say you'd have to consume huge quantities to make any difference. That's not safe, especially if you have a known breast or ovarian cancer risk.

German studies have shown that the herbal supplement Black Cohosh can help alleviate hot flashes. Remifemin is one brand name that's popular.

Researchers have also found that Cohosh contains no estrogen compounds and has no effect on breast cancer.

Promensil is an herbal supplement made from red clover. Studies have shown it can curb hot flashes and night sweats. It may also help to maintain healthy bones.

The Chinese herb Don Quai contains Phyto-estrogens that may also be helpful in relieving hot flashes.

But doctors warn that the data on all of these is very limited. Much more research is needed before most medical professionals will recommend herbal supplements as alternatives to HRT. Is it safe to try them? You should ask your doctor first.

Researchers have found that the problems with herbal medicines include allergic reactions and interactions with prescription drugs. That's why it's important to talk to your doctor before you decide to take any supplement.