Salicylic acid was converted into its O-glucoside when administered to cell suspension cultures of Mallotus japonicus. The efficiency of the glucosylation was highest in the cells grown in Linsmaier-Skoog medium containing 1 μM 2,4-dichlorophenoxy-acetic acid at any scale of culture (7 ml - 3 1). The yield of salicylic acid-O-glucoside could be increased up to 1.1 g/l by continuously dripping a non-toxic amount of salicylic acid (5.8 mg/31 medium/h) to a 51 fermenter during a culture period of 14 d.