In this paper, a closed-loop control system was developed using fuzzy logic to adapt the parameters of a pharmacokinetic (PK) model. The system is based on a two-compartment PK model with first-order rate process of oral administration. The fuzzy logic adaptation scheme uses the error and the change in error as the input variables. The output variable of the fuzzy controller is the scaling factor to adjust the PK parameter. The fuzzy controller adjusted the real situation concentration to the reference value derived from the parameters of population mean data according to the established rule-base. The simulation results show that the controller provides good performance to adjust the concentration with the reference values. 漏 (2013) Trans Tech Publications, Switzerland.