Krill oil is oil obtained from a small, shrimp-like animal. Baleen whales, mantas, and whale sharks primarily eat krill. The word "krill" in Norwegian means "whale food". People extract the oil from the krill, place it in capsules and use it as a medicine. Some brands of krill oil products indicate that they are using Antarctic krill. This often refers to the type of krill called Euphausia Superba.

Krill oil is most often taken by mouth for heart disease, high amounts of certain blood fats (triglycerides) and high cholesterol. It is also used for dry eyes.

Krill oil contains fatty acids similar to fish oil. These oils are thought to be beneficial oils that reduce swelling, lower cholesterol and make blood platelets less sticky. When blood platelets are less sticky, they are less likely to form clots.

Other effects of krill oil:

It is used to delay aging on the skin.
It lowers cholesterol in high cholesterol.
It lowers high blood fat. (Triglyceride lowering)
Used in osteoarthritis treatments.
Used in premenstrual syndrome.
Used in rheumatoid arthritis treatments.
It protects against cancer.
It is used in depression treatments.
It is used in the treatment of stroke.