Background: Trends in modern pharmaceutical science show an increase in demand for new drugs and diet supplements derived from natural products, while during the last decades, great research is conducted regarding the natural compounds and their medicinal and bioactive properties. Organosulfur compounds are present in many plants and their bioactive properties have been used in folk and traditional medicine throughout the centuries. Not until recently, modern science confirmed and revealed the chemical compounds that are responsible for these properties, the chemistry involved in their biosynthesis and the main mechanisms of action. Keywords: Alliin, allium, brassica, garlic, glucosinolates, onion, thiosulfinates.