Nobiliside A, a new triterpene glycoside, exhibits some biological activities including antifungal and cytotoxic effects. A LC/MS/MS method was developed and validated for determination of Nobiliside A in rat plasma, would prove to be useful for other pharmacokinetic assessments. Male SD rats were housed in Medicilon animal facility. The animal experiments of the present study were approved by IACUC of Medicilon and were carried out in accordance with the SOPs of the facility.