The solid-phase method for hydrogenolysis, hydrogenation and isotope exchange reactions is described. Its potential for tritium labelling of organic compounds including lipids, nucleotides, amino acids, peptides and pharmaceuticals is demonstrated. The influence of the reaction conditions on the yield and specific radioactivity of the labelled compounds is considered. It is shown that results can be interpreted by the dependence of tritium spillover reactions on the nature of the initial compound and other factors.