Organic solvents are expected to be readily absorbed through the skin or by inhalation. Toxicokinetic models are used to describe the time course of absorption and elimination. Special attention is given in this review to simulation models in which rate constants are derived from physiological parameters of the exposed subject and from physicochemical properties of the inhaled chemical. Such a simulation model is used to gain insight into the uptake, distribution, and elimination of inhaled vapors of organic solvents. Large differences between kinetic patterns of hydrophobic and hydrophilic solvents are indicated by the effects of biosolubility, exposure duration, concentration fluctuation on the uptake, distribution and elimination of solvents, etc. -- AATA