What Are the Side Effects of Taking Krill Oil?

People allergic to krill oil may experience difficulty breathing, hives, and swelling of the lips, tongue, throat or face, explains Drugs.com. It is necessary to stop using the oil if serious side effects occur, including chest pain, irregular heartbeats and flu symptoms. Less serious side effects include moderate skin rash, back pain and fishy aftertaste.

Krill oil is a supplement made by extracting the oil from the small, shrimp-like animal known as krill, the primary food source of whale sharks and baleen whales. According to WebMD, krill oil is similar to fish oil in that it contains fatty acids that may help decrease swelling, preventing blood clotting and lower cholesterol. It is often used to treat high triglyceride levels, high blood pressure, high cholesterol, heart disease and painful menstruation. It has also been used for depression, cancer, PMS, stroke and osteoarthritis. However, its effectiveness in treating these conditions has not been adequately studied.

To avoid any possible side effects, it is necessary to take krill oil as directed by a doctor, explains Drugs.com. People with a fish allergy should not use the oil, and patients taking anticoagulants should inform their doctor before taking krill oil. Those suffering from diabetes, pancreas disorder, liver disease, underactive thyroid or blood clotting problems should ask the doctor before using the supplement. Pregnant and breastfeeding women should also seek a doctor's advice.

Doctors recommend taking krill oil as a whole without opening or puncturing the capsule, states Drugs.com. It is important to engage in exercises and to follow a healthy diet while using krill oil. There may be medications that interact with krill oil, such as vitamin, herbal, prescription and over-the-counter products, so patients should inform the doctor about current medications. Krill oil is a dietary supplement and does not need a prescription. As of 2015, U.S. Food and Drug Administration has no specific recommendations for krill oil.