An efficient system was developed for the in vitro micropropagation and hairy root culture of Ophiorrhiza alata Craib for camptothecin (CPT) production. Shoot multiplication on leaf and node explants from germinated seeds of O. alata was successful on half-strength Murashige and Skoog medium supplemented with varying amounts of kinetin and alpha-naphthaleneacetic acid. Node explants grown in vitro were successfully infected by Agrobacterium rhizogenes TISTR 1450 for the establishment of hairy root culture. The amount of CPT in various parts of O. alata was analyzed by HPLC. The accumulation of CPT in transformed hairy roots was twice that in soil-grown plants (785 +/- A 52 and 388 +/- A 32 mu g/g dry wt, respectively). In the presence of a polystyrene resin (Diaion HP-20) that absorbed CPT, the CPT content in the culture media increased sevenfold compared with controls (1,036 and 151 mu g per 250 ml medium, respectively). These results enable the feasible production of CPT of O. alata by means of a cell culture strategy. These measures can help safeguard the plant from extinction.