Ground flaxseed may increase the number of bowel movements you have each day or may cause the more extreme side effect of diarrhea. In fact, it's actually used as a laxative to treat constipation, according to the University of Maryland Medical Center. You may also experience other gastrointestinal side effects, such as nausea, gas, bloating, abdominal pain and a stomachache. Ground flaxseed works as a bulk-forming laxative, which means it absorbs water and makes larger, softer stools. This type of laxative can have the opposite effect, however, and block your intestine if you consume too much.
