Abstract: OBJECTIVE To determine the level of native thiols (-SH) and total -SH in goat horn extract and rat plasma. METHODS The thiols levels in goat horn extract and rat plasma were measured using the classical Ellman reagent method. Both the levels of native -SH and total -SH in rat plasma were measured after oral administration of goat horn extract. After oral administration of goat horn extract， the native -SH level in rat plasma was measured， and the curve of -SH level against time after administration was obtained. RESULTS The level of native -SH in goat horn extract ranged from 3.96 to 5.08 mmol/L， and the level of total -SH in goat horn extract ranged from 4.52-5.94 mmol/L. After continuously oral administration of goat horn extract， both the levels of native -SH and total -SH in rat plasma significantly increased (P<0.01) compared with normal rat from d4 to d7. Oral administration of Aspirin did not significantly increase the -SH level in rat plasma. In addition， 30 min after oral administration of goat horn extract， the level of native -SH in rat plasma significantly increased to (10.16±1.18)mmol/L， and 8 h later， the level of native -SH in plasma reverted to normal level. CONCLUSION There are abundant -SH contained components in goat horn extract， and goat horn extract could obviously increase the -SH level in rat plasms. The results in the present study suggested that -SH group contained components might be the important material basis of goat horn. It provides a reference for investigations on animal horn derived TCMs.