Hypericum perforatum is an important medicinal plant containing numerous biologically active compounds. The effect of chitosan elicitation on xanthone biosynthesis in calli and in cell suspension cultures of H. perforatum subsp. angustifolium was evaluated. Elicited cell cultures showed an increase in xanthone production and a simultaneous decrease in flavonoid production. Chitosan also induced the production of 1,7-dihydroxyxanthone (euxanthone) and cadensin G, which were not detected in either the calli nor the non-elicited cell cultures. 1,7-Dihydroxyxanthone was in part (21%) released in the culture medium.