Background Flaxseed has had a variety of health and industrial uses. Hippocrates wrote about flaxseed being a laxative; North American pioneers made flaxseed dressings for cuts and burns. Fiber from the plant is made into linen, and oil from its seeds is used in paints, among other products. Today, flaxseed and flaxseed oil are promoted for a variety of disorders that include stomach and intestinal complaints, such as constipation, diarrhea, and irritable bowel syndrome (IBS). Flaxseed and flaxseed oil are also promoted for heart and blood vessel disorders (for example, high levels of blood fats such as cholesterol and triglycerides), as well as diabetes and other conditions. How Much Do We Know? A number of studies in people have investigated the health effects of flaxseed and flaxseed oil, particularly how flaxseed may affect heart and blood vessel diseases, type 2 diabetes, and menopausal symptoms. What Have We Learned? Flaxseed contains …