1. Diallyl disulphide (DADS), a compound formed from the organosulphur compounds present in garlic, is known for its anticarcinogenic effects in animal models. 2. The aim was to identify and analyse the metabolites produced in vivo after a single oral administration of 200 mg kg(-1) DADS to rats. The organic sulphur metabolites present in the stomach, liver, plasma and urine were measured by gas chromatography coupled with mass spectrometry over 15 days. 3. Data indicate that DADS is absorbed and transformed into allyl mercaptan, allyl methyl sulphide, allyl methyl sulphoxide (AMSO) and allyl methyl sulphone (AMSO(2)), which are detected throughout the excretion period. Overall, the highest amounts of metabolites were measured 48-72h after the DADS administration. AMSO(2) is the most abundant and persistent of these compounds. The levels of all the sulphur compounds rapidly decline within the first week after administration and disappear during the second week. Only AMSO and AMSO(2) are significantly excreted in urine. 4. These potential metabolites are thought to be active in the target tissues. Our data warrant further studies to check this hypothesis.