Arginine is an amino acid found in many foods, including dairy products, meat, poultry, and fish. It plays a role in several important mechanisms in the body, including cell division, wound healing, removal of ammonia from the body, immunity to illness, and the secretion of important hormones.

The body also uses arginine to make nitric oxide (NO), a substance that relaxes blood vessels and also exerts numerous other effects in the body. Based on this, arginine has been proposed as a treatment for various cardiovascular diseases, including congestive heart failure and intermittent claudication, as well as impotence, female sexual dysfunction, interstitial cystitis, and many other conditions. Arginine's potential effects on immunity have also created an interest in using it as part of an "immune cocktail" given to severely ill hospitalized patients and also for preventing colds.

Normally, the body either gets enough arginine from food, or manufactures all it needs from other widely available nutrients. Certain stresses, such as severe burns, infections, and injuries, can deplete your body's supply of arginine. For this reason, arginine (combined with other nutrients) is used in a hospital setting to help enhance recovery from severe injury or illness.

Arginine is found in dairy products, meat, poultry, fish, nuts, and chocolate.