Doctors and their herbalist ancestors have been treating nightsweats for at least 1800 years since the writing of the Shang Han Lun, a second-century Chinese medical textbook that taught that these bouts of nocturnal perspiration were the result of kidneys sending fluids backwards in the body.

The modern understanding of nightsweats is more nuanced. They often have a hormonal cause, but the cause is not always related to estrogen.

Hot flashes at night may be related to the increase of follicle-stimulating hormone (FSH) accompanying menopause or surgical removal of the ovaries, diabetes, or malaria. The causes of profuse sweating in winter in men are, of course, more likely related to diabetes or the parasitic disease malaria. Hot flashes occur day and night in men treated for prostate cancer.

The key to understanding menopause and nightsweats is that if the condition is related to menopause, then episodes tend to occur at the same time every night. They may be worse after drinking alcohol or sudden change of temperature. African-American women are especially susceptible to uncontrollable nighttime perspiration even without alcohol or sudden change of temperature.

There is a direct relationship between sweaty flushes and diabetes. Diabetics who get this condition tend to have episodes the same number of hours after eating, but not at the same time every night. Perspiration after going to bed and weight loss are a common warning of undiagnosed diabetes and are a reason to see a physician.

And nightsweats accompanying malaria are "tidal," that is, they build up and taper down. Malarial sweats alternate with chills, and occur on a regular schedule whether the sufferer is sleeping or not.

Male survivors of prostate cancer typically have their sweaty symptoms increasing or decreasing during the course of cancer therapy.

So how do you treat this condition naturally?

Nightsweats aren't really the result of "toxins," but rather of hormones out of balance that are acting as if they were toxins. In women who have reached menopause, this condition is often treated with estrogen, but black cohosh (300-1,000 mg daily) and soy isoflavones (not to be confused with soy foods, but a supplement of concentrated daidzein + genistein, up to 400 mg) daily offer relief to many.

Women who are planning to discontinue estrogen replacement therapy (ERT) may want to begin a supplementation routine up to six months before ending ERT. This allows the effects of the herbs to build up over time. It is also possible to use both ERT and herbal therapies.

Women who have had breast cancer may respond better to soy foods than to soy supplements.

What else can be done?

• Avoid sudden changes in temperature just before bedtime, such as taking a hot bath or moving from a warm living room to a cooler bedroom. Cooler bedroom temperatures, however, reduce the severity of hot flashes.
• A research study at Vanderbilt University found that magnet therapy does in fact relieve hot flashes, but it doesn't make any difference whether the magnets are magnetized or not. Small weights on limited areas of skin seem to reduce the severity of sweating during nighttime hours.
• Treating constipation and other digestive disturbances usually reduces the severity of nighttime sweating over a period of 2-3 months.
• The Asian herb dong quai may reduce episodes of nighttime sweating, but it is more effective in women who have completed menopause than those who are in perimenopause.

Nocturnal perspiration related to diabetes or malaria responds to treatment of the underlying condition.

There is one other, relatively rare cause of sweating at night: acid reflux, also known as heartburn. Controlling heartburn will eliminate nightsweats if it is the cause.

Author or co-author of nine books on natural healing, Robert Rister is currently blogging on alternative pancreatic cancer therapies.