Anthraquinones (AQs), secondary metabolites produced by suspension cultures of Morinda citrifolia, are excreted to a low extent under physiological conditions. When 2% (w/v) of the nonionic surfactant Pluronic F-68 was added, the concentration of the extracellular AQs significantly increased. Elicitation of the cell growth and AQ production occurred with 0.035-2% (w/v) of the surfactant. By using a two-phase system with n-hexadecane as organic component, anthraquinones were extracted from the growth medium into the organic, second phase. The overall production of AQs in the presence of hexadecane and Pluronic F-68 (0.11%, w/v) was twofold the control value.