Suspension cultures of Sussurea medusa produce jaceosidin and hispidulin. In an attempt to increase productivity, silver nitrate and glutathione (GSH) elicitors were tested. Both dosage and addition time as well as time course studies were carried out on the effects of the elicitors on the formation of the metabolites. Silver nitrate and glutathione elicitors increased the production of jaceosidin and hispidulin (from ca. 32.01 to 51.25 mg l(-1) and 3.11 to 5.13 mg l(-1)) at optimum dosage and addition time, respectively. Silver nitrate and glutathione in a combination were added at concentrations of 0.01 and 1 mmol l(-1) on days 0 and 5 to cultures of S. medusa, jaceosidin and hispidulin production reached 84.3 and 7.9 mg l(-1), respectively, which were 2.6 and 2.5 times higher than that in controls and was higher than for each elicitor alone. It was also found that glutathione enhanced phenylalanine ammonialyase (PAL) activity while silver nitrate did not. (C) 2004 Elsevier Ltd. All rights reserved.