Too much of a good thing can be bad for you. People who've taken flax seed in large doses have reported minor but annoying side effects like stomachache, flatulence and diarrhea.
Because of its laxative effect, people suffering from bowel disorders are advised to avoid consuming flax seed in crushed or powdered form but can take the oil if they really want to try the supplement [source: Medline Plus].
Although the omega-3 fatty acids in flax seeds help reduce swelling, which is generally a good thing, they can also slow the formation of blood clots and increase bleeding. That's why those taking blood thinning medications like Coumadin or aspirin, or similar herbal remedies like gingko biloba and saw palmetto, should consult their doctor before adding flax seed to their diet [source: Herb Wisdom].
Women with health problems related to hormonal imbalance, such as endometriosis, should also be cautious about taking flax seeds because they can mimic the biological effects of estrogen. It is also not recommended for women who are pregnant or breastfeeding [source: Medline Plus].
Some proponents of the supplement advocate taking flax seed supplements, but warn they should not be used exclusively. Overuse of flax, in the absence of other fat sources, can lead to an omega-6 deficiency, which can cause health problems just as severe as a lack of omega-3 [source: Erasmus].
Flax seed has the potential to do much more than balance out your fatty acids. Continue reading to learn about the seed's effect on prostate cancer.