Carnosine (β-alanyl-L-histidine) is a dipeptide that occurs endogenously in the body, the level of which decreases with age. It is a natural neuroprotective substance and its presence in the body prevents the processes of senescence – the aging of cells. In addition, it has antioxidant and chelating properties in relation to heavy metal ions. Carnosine maintains an acidalkaline balance – it buffers excitable tissues and also neutralizes lactic acid produced as a result of anaerobic glycolysis. It supports myocardial contractility by regulating the activity of calcium channels in cardiomyocytes and skeletal muscles. It limits the toxicity of free oxygen radicals and aldehydes – removing toxic products resulting from free radical reactions. As an anti-glycoprotein, it protects the cellular proteins against reactive oxygen species. It is bacteriostatic in relation to Helicobacter pylori. Carnosine is recognized as a potential therapeutic agent for many diseases correlated with the aging process. This substance is a potential therapeutic agent in the case of Parkinson’s and Alzheimer’s disease, as well as ischemic stroke. It reduces the level of pro-inflammatory cytokins and also has a potential anti-tumour effect. In addition, it counteracts the development of cataracts. This work is a review of the bioactive properties of carnosine and presents current cases of use of this substance in the manufacture of pharmaceuticals. This substance is becoming more and more popular as a component of dietary supplements.