The paper sums up new experimental knowledge concerning the individual groups of organic sulfurous substances of the garlic: sulfoxides, thiosulfinates, ajoens, vinyldithiines, alkyl and alkene sulfides and glutamylpeptides of sulfurous amino acids, their transformation reactions (based on the temperature, pH, extraction medium, and time) and the final products of transformations (Scheme 1, 2). It deals with the activity of the enzyme alliinase necessary for the transformation of sulfoxides present in the whole garlic, its isolation and stability as well as the stability of the dominant thiosulfinate allicin in various media and simulated body fluids. It refers to the studies of the metabolism and transformations of the most important sulfurous components performed in vitro on the hepatocytes and on the isolated rat liver, and those carried out in vivo on the rats and including the examination of the composition of the exhaled air. It follows from published papers that all different degradation products of thiosulfinates, mainly the prevailing allicin, are carriers of various biological activities. The paper also lists the types of commercial preparations prepared from the garlic, their differences, and considerable variability of their contents of active principles.

        Key words: Allium sativum – thiosulfinates – allicin – ajoens – vinyldithiines