The paper describes the modelling of coriander essential oil extraction by steam distillation. Two models are applied: the first one takes only diffusion into account, in the second the solution of the transferred species is additionally modelled. The model is formulated as the system of partial differential equations. It is space discretized and than solved using Runge-Kutta method. The comparison of the simulation results with experimental data shows that the more complex model gives good agreement with experimental data.