Sulphur, besides being an integral element of several macromolecular cell constituents, appears in a series of low-molecular weight, partly ubiquitously distributed compounds, e. . S-containing protein amino acids, coenzyme A, S-adenosyl methionine, thiamine, and biotin, without which a steady state of living cells cannot be maintained. These, however, are not included in the present discussion. Rather, an attempt is being made to illustrate, by way of examples, the vast structural variation in other organic sulphur compounds with, as far as we know, a discontinuous. distribution within the plant and animal kingdom. The chemical characteristics of these compounds are variegated, encompassing, inter alia, mercaptans, thiolesters, disulphides, sulphides (linear, cyclic, aromatic, and heterocyclic), amino acids, thioglycosides, terpenoids, sulphoxides, sulphones, and sulphates, the origin, transformations, and biological importance of which are mostly unknown. A bird'seye view of the area is presented in the hope that this, however incomplete and blurred, may reveal some less obvious relationships and thus serve to invigorate further activity within the field.