The scientists selected a group of 40 patients who had developed mild to moderate dementia--or memory loss and confusion--after having a number of small strokes.

Twenty-five patients took an extract that contained ginseng root and leaves plus another herb known as panax notoginseng, three times a day for 12 weeks.

The other 15 patients took Duxil (almitrine plus raubasine), a drug thought to improve oxygen delivery to the brain that has been used for dementia in the elderly.

Dr. Jinzhou Tian and associates at the University of Beijing conducted a battery of tests that measured the patients' ability to recall words and stories, verbal recognition, and visual recognition.

Patients taking the ginseng compound showed more improvement in overall memory than patients in the Duxil group, Tian said in results prepared for the American Stroke Association's 28th International Stroke Conference.

Robert J. Adams, chairman of the Stroke Council of the American Heart Association, stressed that this study was very preliminary, and that placebo-controlled studies and more safety data were need.

"At this time, a recommendation to use this herb for memory enhancement would be premature," he said.