Plant cell and suspension cultures have been established from stem cuttings of Picrasma quassioides Bennett. The effect of 244 different types/concentrations of plant growth regulators on growth and quassin accumulation in callus tissue was investigated. Best growth, in terms of wet/dry weight after four weeks growth, was obtained on B5 media supplemented with 2% glucose, 10% coconut milk, 0.5 mg.l(-1) zeatin riboside and 1.5 mg.l(-1) IBA. The highest yields of quassin (0.014-0.018%) were detected on this same media supplemented with 1.0 mg.l(-1) IBA and varying concentrations of zeatin riboside. Suspension cultures were easily established on B5 media supplemented with 2% glucose, 1.0 mg.l(-1) 2,4-D and 0.5 mg.l(-1) kinetin. The carbon source had a marked effect on quassin accumulation with 0.32% quassin being detected when cells were grown in 2% galactose. This is comparable to the highest reported quassin yield for the whole plant.