Can Fish Oil Cause Abdominal Gas?

Fish oil capsules spilling out of a bottle.
Image Credit: PeoGeo/iStock/Getty Images

Fish oil, which contains omega-3 fatty acids, may provide a number of health benefits, including lowering your risk for heart disease, heart attack, stroke, high blood pressure, arthritis and cancer. Fish oil supplements may also help you lower you triglyceride levels. However, fish oil supplements can cause side effects, including abdominal gas.

Abdominal Gas

Gastrointestinal disturbances, including abdominal gas, bloating, abdominal pain and belching, sometimes occur when you take fish oil supplements. However, most people do not experience these adverse effects. An article published in "Circulation" in 2002 noted that in two studies on the use of fish oil only 4.9 percent and 8 percent of participants reported gastrointestinal side effects.


Other Side Effects and Interactions

A more common side effect from fish oil supplements is a fishy aftertaste. Some people also experience heartburn, acid reflux, nausea, diarrhea, nose bleeds, rash, increases in blood sugar or decreases in blood pressure. Check with your doctor before taking fish oil, as it may interact with blood thinners, vitamin E and blood pressure medications or cause you to need a higher dosage of diabetes medications.

Minimizing Side Effects

If you experience abdominal gas when you take fish oil supplements, you can take steps to minimize this side effect. Try splitting up your fish oil dosage throughout the day, starting with a smaller dose and building up to a higher dose, taking your fish oil along with meals, taking a time-release fish oil supplement or freezing your fish oil supplements before you take them.



There is a small risk that some fish oil supplements could be contaminated with mercury, PCBs or other contaminants, so choose supplements from a well-known manufacturer to limit this risk. Do not take 3 grams per day or more of fish oil unless you are under a doctor's supervision, as this can cause serious side effects, potentially increasing your risk for bleeding and lowering your immune response.