High doses of American ginseng, the herb, over two months have reduced cancer-related fatigue in patients more effectively than a placebo, according to a study presented Monday at the annual meeting of American Society of Clinical Oncology. Researchers studied 340 patients who had completed cancer treatment or were being treated for cancer at one of 40 community medical centers in the United States. Sixty percent of patients studied had breast cancer. Each day, participants received a placebo or 2,000 milligrams of ginseng administered in capsules containing pure, ground American ginseng root. According to the study, the pure ginseng provided only a slight improvement in fatigue symptoms in four weeks, but in eight weeks, it offered cancer patients significant improvement in general exhaustion, such as feelings of being \"pooped,\" \"worn out,\" \" fatigued,\" \"sluggish,\" \"run-down,\" or \"tired\", when compared to the control group with placebo. \"After eight weeks, we saw a 20-point improvement in fatigue in cancer patients, measured on a 100-point, standardized fatigue scale,\" said Debra Barton of the Mayo Clinic Cancer Center based in the U.S. state of Minnesota, adding that the herb had no apparent side effects. Ginseng has long been used in traditional Chinese medicine as a natural energy booster. Until this study, its effects had not been tested extensively against the debilitating fatigue that occurs in up to 90 percent of cancer patients. Fatigue in cancer patients has been linked to an increase in the immune system\'s inflammatory cytokines as well as poorly regulated levels of the stress-hormone cortisol. Ginseng\'s active ingredients, called ginsenosides, have been shown in animal studies to reduce cytokines related to inflammation and help regulate cortisol levels.