The interest of Europeans in alternatives to the Western Medicine increased in the last few years and will be increasing the next time. Patients are looking for alternitives to synthetic remedies with its numerous side effects. One of the alternatives is the TCM. This medicine is over thousands of years old. The TCM is rich of complex herbal mixtures, which are interesting us. This diploma thesis worked with six traditional herbs, which are also used in the mixture Si Miao San. The aim was to modify an analytical method for the HPLC, to get a method, which is suitable for the LC- MS/MS. An acid was changed first, than the gradient system was modified. Finally a suitable method was carried out and the measurements of the plant extracts started.