Does Fish Oil Cause Bad Breath?

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Fish-oil supplements are generally consumed for heart-health benefits. Side effects are few, with the most common being belching and bad breath with a fishy odor or aftertaste. A variety of tips and remedies may reduce the uncomfortable side effect. Discuss taking the supplement with your doctor or other medical professional to avoid additional side effects or complications. Fish-oil supplements are not controlled by the U.S. Food and Drug Administration and should be carefully monitored.

Fish Odor

Fish-oil supplements may leave you with a fishy odor on your breath or when you burp. The supplement is generally made from tuna, salmon, mackerel or even whale or seal blubber, according to MedlinePlus. Additional unpleasant side effects include gas, bloating and diarrhea.


Consumer Reports suggests freezing your fish-oil supplement or taking it before a meal to minimize the burp effect. Freezing the capsule creates a time-released capsule. As you digest the capsule, it will release the fish oil over a longer period. The fish oil remains effective. Read the label of the supplement to ensure the fish oil may be frozen. When you take the capsules at the beginning of meals, mixing the fish oil and food masks the fishy odor.


Some fish-oil capsules are marketed as odor free. These supplements have an additional coating, allowing the capsule to pass through the stomach and directly into the intestine before being digested. Ask your local nutrition store representative for samples of a supplement before purchasing an entire bottle. Vegetarian omega-3 capsules are 100-percent fish free. The capsules are formed from algae; fish eat the algae for their source of fatty acids.

Additional Side Effects

Fishy breath is embarrassing, but it causes no health risks. Additional side effects that are more severe include increased bleeding and thinning of blood. These may be manifested in increased nosebleeds and bruising of the skin. Take precautions when using fish oil in combination with blood pressure medications and anticoagulant drugs. Your blood may take longer to clot, and your blood pressure may drop to abnormally low levels.