Abstract: This paper studied the effect of the total extract of Hypericum perforatum L. on Corynebacterium glutamicum and Alcaligenes faecalis with illumination and without illumination. The result showed that the total extract had strong bactericidal effect on Corynebacterium gluta-micum and inhibitory effect on Alcaligenes faecalis and the effect depended on its concentrations but was independent of illumination.