In this laboratory activity, students are introduced to the synthesis of an albendazole metabolite obtained by a sulfide oxidation reaction. Albendazole as well as its metabolite, albendazole sulfoxide, are used as anthelmintic drugs. The oxidation reagent is H[subscript 2]O[subscript 2] in acetic acid. The reaction is environmental friendly, fast, and proceeds with high yield. The crude reaction is analyzed by HPLC chromatography to determine purity. The simplicity of the experiment allows students to study chiral concepts, physicochemical and spectroscopic properties of the compounds, and HPLC determinations. (Contains 2 figures.)