Medieval physicians believed health was the balance of mysterious fluids called "humors," and a Swedish physician has some new evidence that humor, in its modern sense, is also a healer.

Dr. Lars Ljungdahl of the Lyckorna Primary Health-Care Centre in Motala, Sweden, reports that six women got significant relief from painful symptoms of muscle-bone disorders and depression with a course of "humor therapy."Laughter corresponded with relief from symptoms, and the greatest symptomatic relief occurred in people who had greatest degrees of amusement, Ljungdahl said in a letter in today's Journal of the American Medical Association.

Ljungdahl said one male and two female nurses participated in 13 meetings of a "humor group" with the patients, ages 26 to 48.

"We used funny books, records, and videofilms and learned to give higher priority to humor in our everyday lives," he wrote. "The program also involved lectures on humor research and the regular use of relaxation programs, with suggestions that stimulated humor and joy."

He noted that relief was significantly greater during weeks seven through 13 than during weeks one through six, indicating regular laughter had the greatest benefits.

Degrees of amusement and relief were graded by the patients on separate scales, he said.

Independent psychological tests before and after humor therapy revealed an overall improvement in general psychological well-being, he said.

"The study suggests that a humor therapy program can increase the quality of life for patients with chronic problems and that laughter has an immediate symptom-relieving effect for these patients," Ljungdahl wrote.

"Their self-confidence also seemed to increase, they coped more ably with their symptoms and allowed theselves to be happy and enjoy life regardless of their medical problems," he said.

Ljungdahl acknowledged that his study results were only preliminary - because of the small number of patients involved, the lack of a comparison group of healthy patients and the uncertainty of measurements.

Such studies are now under way, both in the United States and in Great Britain.