Side effects from flax seed use affect the gastrointestinal system. Symptoms caused by ingesting too much flax include gas, bloating, constipation and diarrhea, as stated by Medical News Today.
Pregnant or breastfeeding mothers should avoid using flax seed, either ground or in oil form. Because the seeds have properties resembling estrogen, they could interfere with a healthy pregnancy or cause problems with milk production, according to Medical News Today.
Persons suffering from Crohn's disease should speak with their doctors before consuming anything that contains flax seeds. Because the seeds' side effects affect the bowels, they could increase the inflammatory response within the colon, reports Drugs.com.