Injecting botulinus toxin, best known as a cause of food poisoning, into the armpits of people who have a medical condition that makes them sweat excessively can rapidly and dramatically reduce the problem, German researchers say.

Tests of 145 volunteers suffering from a condition known as hyperhidrosis, or excessive sweating, found that the injections reduced perspiration by 86 percent, a team led by Dr. Marc Heckmann of the Ludwig-Maximilians University in Munich said in Thursday's New England Journal of Medicine.

The doctors used botulinum toxin A to treat people whose sweat glands oozed an extraordinary amount of fluid.

At the start of the study, patients were perspiring an average of 17.5 ounces (490 grams) of underarm sweat per day, enough to fill a soft drink bottle.

By the time they were tested again, two weeks after the injections, the daily rate dipped to 2.4 ounces (67 grams) per day.

But the effect of the injections was not permanent. After the initial, dramatic drop, sweat production began inching upward. Still, by the 26th week, the amount of sweat generated by the armpits was still about one-third the original level.

"For sustained relief," Heckmann and his colleagues said, "additional injections of botulinum toxin A at varying intervals are usually required."

Hyperhidrosis, or excessive uncontrolled sweating, usually appears at the armpits, the palms or the soles of the feet. The problem can be extremely embarrassing.

Doctors usually try to treat it with aluminum chloride, similar to the chemical found in antiperspirants, or two types of drugs. But aluminum chloride can cause skin irritation and the drugs can have negative side effects.

Another treatment is iontophoresis, which requires putting electrodes encased in wet sponges under each armpit and applying low voltage of electricity to the skin for 20 minutes several days a week, producing a stinging sensation.

Surgery to remove some sweat glands is another option.

Botulism toxin is already used for various conditions where doctors want to disrupt the function of muscles or nerves.

Although there have been sporadic instances where botulism has been used as a treatment for excessive sweating, the new study, conducted in 1999 and the first three months of 2000, involved patients from 24 medical centers in Germany.

Botulinus toxin is made by at least three companies worldwide. The form used in the study was made by Ipsen-Pharma of Ettlingen, Germany.

Botulism is a poisoning resulting from the toxin produced by botulinus bacteria, sometimes found in foods improperly canned or preserved. It is characterized by muscular paralysis and disturbances of vision and breathing, and is often fatal.

(From ChinaDaily)