A pharmacokinetic study based on the distribution of radioactivity from the double labelled S-adenosyl-L-methionine (SAM) has been carried out by oral administration of the liposoluble stable salt [methyl-(14)C, 8-(3)H]SAM N-ole-1-oyltaurate to rats. The SAM sulfate p-toluensulfonate salt, the only SAM salt at present commercialized as drug, was chosen as reference compound to have a comparative pharmacokinetic analysis. The metabolism of the SAM is characterised by a differential use of the two labelled moieties by the various organs, liver being the most active in metabolizing the sulfonium compound with a preferential uptake of the methyl-(14)C fragment. The radioactivity detected after the administration of [methyl-(14)C, 8-(3)H]SAM N-ole-1-oyltaurate is, in all the organs examined, two times higher than the [methyl-(14)C, 8-(3)H]SAM sulfate p-toluensulfonate compound, attesting that the liposoluble [methyl-(14)C, 8-(3)H]SAM N-ole-1-oyltaurate is provided with better bioavailability.