The pharmacokinetics of propylene glycol has been examined during multiple oral-dosing regimens. The glycol is rapidly absorbed, with Cpmax observed within 1 h following administration. The terminal elimination half-life is ∼4 h. After a minimum of 10 half-lives of maintenance dosing on a fixed regimen, the accumulation of propylene glycol differed significantly among individuals because of variability in apparent clearance. The average apparent total body clearance is ∼0.1 L/kg · h and may be concentration dependent. The apparent volume of distribution is ∼0.5 L/kg, approximating total body water.