The aim of this article is to provide information about L-carnitine, its physiological role in the human body and its content in some foods. This chemical compound is mainly synthesized in the liver, kidney and brain and is composed of two aminoacids, lyzine and metionine. L-carnitine regulates the level of acylo-CoA and CoA in the mitochondium and cytozolum, and it provides acetyl moieties for the biosythesis of acetocholine. L-carnitine plays a vital function in the metabolism of lipids and it carries long-chain fatty acids into mitochondria for beta-oxidation. An increase of the amount of L-carnitine in the human body may lead to reduction and inhibition of production of fatty tissue. Despite the fact that human body can synthesise L-carnitine, about 80% of this chemical compound is delivered by food. It is crucial, especially for people who are on a slimming diet, to choose products rich in L-carnitine because this compound may potentially reduce the body weight. Animal by-products contain the highest amount of L-carnitine, and these are, e.g , kangaroo meat (637 mg), horse meat (423mg), beef (139 mg per 100 g of dry weight). The amount of L-carnitine in milk products may range from 1,4 to 42,8 mg per 100 g of dry matter. Vegetables and fruits are products which contain less than 5 mg of L-carnitine per 100 g of dry matter. Lipids are also very low in L-carnitine, e.g sunflower oil is free from this compound. It is worth mentioning that mushrooms are richer in L-carnitine than plants. The amount of L-carnitine (53 mg/100 g dry matter) in pleureotus ostreatus equals approximately 100 g of minced pork.