CHICAGO, Feb. 13 (AP)--Charlie Chaplin beat 1 1/2 hours of weather information in a study of the healing power of humor--no kidding.

The Japanese study found that skin welts shrank in allergy patients who watched Chaplin's comedic classic "Modern Times," but not in patients who watched a video on weather.

"These results suggest that the induction of laughter may play some role in alleviating allergic diseases," said Dr. Hajime Kimata of Unitika Central Hospital in Kyoto Prefecture.

His findings appear in a research letter published in Wednesday's Journal of the American Medical Association.

Kimata was influenced by the author Norman Cousins' 30-year-old research suggesting that laughter and a positive attitude can help reduce pain. Cousins suffered from a life-threatening joint disease and reported that 10 minutes of laughter helped reduce his pain.

Kimata reported on results found after 87 minutes. Twenty-six men and women with allergic skin rashes and allergies to dust mites were given injections of an allergy-producing substance. Their skin welts were measured before and after the videos.

Kimata said exactly how humor might have reduced the welts is not known. But Dr. Margaret Stuber, a professor of psychiatry and biobehavioral sciences at the University of California-Los Angeles, said his premise "makes a lot of sense from a scientific standpoint."

She pointed to a growing body of research suggesting that stress undermines the disease-fighting immune system. Easing stress, which laughter can do, might then have a positive effect.