Can Flaxseeds Make You Sick?

Seeds from the flax plant, commonly called flaxseeds or linseeds, are a widely used herbal remedy taken to treat a variety of health conditions, including heart disease and cancer. While flaxseeds are generally safe and well-tolerated, they may cause side effects in certain individuals. As with any health supplement, consult your doctor before taking flaxseeds.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.


Certain people may be allergic to flaxseeds and may experience an allergic reaction after consuming them. A mild allergic reaction may cause symptoms of itching, rash or hives, as well as nasal congestion and red, watering eyes.

Stomach Symptoms

Flaxseeds contain very high amounts of soluble fiber and people commonly use them as a laxative. Ingesting large amounts of fiber may lead to gastrointestinal effects, including increased bowel movements, nausea, vomiting, gas, bloating or diarrhea. Taking flaxseeds at the same time as other laxatives or stool softeners may increase the risk of diarrhea and other symptoms, advises the American Cancer Society 1.

Intestinal Blockage

The high levels of fiber in flaxseeds can actually make constipation worse if the fiber is not ingested with large amounts of water. In extreme cases, the excess fiber in flaxseeds may cause intestinal blockage. When taking flaxseeds, drink roughly 10 times the volume of water as flaxseeds to avoid constipation or intestinal blockage, explains Blue Cross and Blue Shield of Tennessee.

Other Side Effects

Eating raw or unripe flaxseeds may be toxic and may cause levels of cyanide to rise in the blood, warns Additionally, consuming large amounts of flaxseed may cause symptoms of rapid breathing, shortness of breath, difficulty walking and possibly seizures or paralysis. Cases of hypomania have been reported in people with bipolar disorder after taking flaxseed. Because flaxseeds may exert effects on the body similar to estrogen, changes in the menstrual cycle may occur.