[Studies on chemical components of the volatile oil from the leaves of Hypericum perforatum].

To determine the volatile oil of the leaves from Hypericum perforatum L..The essential oil was obtained by simultaneous distillation and solvent extraction. The chemical components were seperated and identified by GC-MS. The relative contents in the volatile oil were determined by area nomalization.54 chemical constituents were separated and identified representing 92.32% of the total contents.Sesquiterpenes are major chemical constituents in the oil from the leaves of Hypericum perforatum L.. They are very different from those of the essential oil from the same species from the other country.