Ginseng was used to treat fatigue amongst cancer patients, whereas flaxseed was shown to slow prostate tumor growth.
The group of patients assigned a 1000 mg dose of ginseng reported the greatest improvement in terms of fatigue. Researchers caution that the high-quality ginseng also played a role, explaining that a less pure form may not be as effective.
In the Duke University study on flaxseed, doctors found that cancer cells from the tumors of men who took flaxseed were dividing at a slower rate than cells from men who did not. Dr. Andrew Weil suggests than men add fresh ground flaxseed to their diet, but not add flaxseed oil, as that could increase prostate cancer risk. More information on the studies can be found here.
U.S. consumer sales of flaxseed and the entire plant oil supplement category totaled $253 million in 2007, according to NBJ estimates.