| Uses based on scientific evidence | Evidence |
| Laxative (flaxseed, not flaxseed oil) Early studies in humans suggest that flaxseed can be used as a laxative. However, more information is needed to compare effectiveness and dosing to more commonly used agents. | Good scientific evidence for this use |
| Attention deficit hyperactivity disorder (ADHD) Preliminary evidence supports the idea that deficiencies or imbalances in certain highly unsaturated fatty acids may contribute to attention deficit hyperactivity disorder (ADHD). Based on one trial, alpha linolenic acid-rich nutritional supplementation in the form of flax oil may improve symptoms of ADHD. More research is needed to confirm these results. | Unclear scientific evidence for this use |
| Breast cancer (flaxseed, not flaxseed oil) There is currently no information from human studies that flaxseed is effective in preventing or treating breast cancer. | Unclear scientific evidence for this use |
| Diabetes (flaxseed, not flaxseed oil) Human studies on the effect of flaxseed on blood sugar levels report mixed results. Flaxseed cannot be recommended as a treatment for diabetes at this time. | Unclear scientific evidence for this use |
| Heart disease (flaxseed and flaxseed oil) People who have had a heart attack are reported to benefit from diets rich in alpha-linolenic acid, which is found in flaxseed. Good studies that examine the effect of flaxseed on heart disease in humans are not available. It is unclear whether flaxseed supplementation alters the course of heart disease. | Unclear scientific evidence for this use |
| High blood pressure (flaxseed, not flaxseed oil) In animals, diets high in flaxseed have mixed effects on blood pressure. One study in humans suggests that flaxseed might lower blood pressure. The evidence in this area is not clear, and more research is needed before a recommendation can be made. | Unclear scientific evidence for this use |
| High cholesterol or triglycerides (flaxseed and flaxseed oil) In laboratory and animal studies, flaxseed and flaxseed oil are reported to lower blood cholesterol levels. Effects on blood triglyceride levels in animals are unclear, with increased levels in some research, and decreased levels in other research. Human studies in this area report mixed results, with decreased blood levels of total cholesterol and low-density lipoprotein ("bad cholesterol") in some studies, but no effect in other studies. Most human research has not been well-designed, and further research is needed before a recommendation can be made. | Unclear scientific evidence for this use |
| HIV/AIDS No strong evidence is available in this area, and no recommendation can be made without further research. | Unclear scientific evidence for this use |
| Kidney disease/Lupus nephritis (flaxseed, not flaxseed oil) No strong evidence is available in this area. More research is needed before a recommendation can be made. | Unclear scientific evidence for this use |
| Menopausal symptoms There is preliminary evidence from randomized controlled trials that flaxseed oil may help decrease mild menopausal symptoms. Additional research is necessary before a clear conclusion can be drawn and this remains an area of controversy. Patients should consult a doctor and pharmacist about treatment options before starting a new therapy. Overall effects on bone mineral density and lipid profiles remain unclear. | Unclear scientific evidence for this use |
| Menstrual breast pain (flaxseed, not flaxseed oil) Early information from one study in women, the results of which have not been fully reported, suggests that flaxseed may reduce menstrual breast pain. However, further study is needed before a recommendation can be made. | Unclear scientific evidence for this use |
| Prostate cancer (flaxseed, not flaxseed oil) There is limited high quality research of the effects of flaxseed or alpha-linolenic acid (which is in flaxseed) on the risk of developing prostate cancer. This area remains controversial as there is some data reporting possible increased risk of prostate cancer with alpha linolenic acid. Prostate cancer should be treated by a medical oncologist. | Fair scientific evidence against this use |
