Effect of chitosan elicitor on growth and phenylethanoid glycosides (PeGs) accumulation in Cistanche deserticola cell suspension cultures was investigated. PeGs accumulation was dramatically improved by addition of selected chitosan at optimal elicitation conditions. Furthermore, a strategy of repeated addition of the chitosan elicitor for enhancing PeGs accumulation was developed. The chitosan elicitor of 10 mg l(-1)-medium repeatedly added on days 15 and 17 improved PeGs accumulation further, and the final PeGs production in the treated cell cultures of C. deserticola reached 364.6 mg l(-1), which was 3.4-fold higher than that of the control without elicitation. The increase of PeGs accumulation in C. deserticola cell suspension cultures was related to the increase of phenylalanine ammonium lyase activity stimulated by the chitosan elicitor.