Abstract: Nitazoxanide, a new broad-spectrum parasiticidal agent was rapidly deacetylated to tizoxanide, followed by the formation of glucurono-conjugate after dog oral administration. In this experiment, neutral loss scan and full scan mode of triple quatrupole mass spectrometer and enzyme hydrolysis were used to identify the glucuronide of tizoxanide. The results show that neutral loss scan is a useful tool for identification of conjugate metabolites.