Abused solvents have effects similar to those of abused depressant drugs. This experiment evaluated the time course of the discriminative stimulus effects of toluene and 1,1,1-trichloroethane (TRI). Mice were trained to discriminate between i.p. injections of ethanol (EtOH; 1.25 g/kg) and saline in a two-lever operant task in which responding was under the control of a fixed-ratio 20 schedule. After 20-min inhalation exposures to toluene (500-6000 ppm) or TRI (1000-12,000 ppm), stimulus generalization was examined at 0, 5, 10, 20, and 40 min post-exposure. Ethanol doses>or=0.25 g/kg produced increases in EtOH-lever responding with full substitution occurring immediately after testing for doses between 1.25 and 2.5 g/kg. Toluene and TRI produced increased EtOH-lever responding at 0-10 min post-exposure with some EtOH-lever responding occurring up to 20-min post-exposure. Response rates were not decreased for any concentration of toluene or TRI immediately following inhalant exposure but several concentrations elevated rates from 5 to 40 min post-exposure. These results confirm and extend previous studies and show these solvents produce similar effects in EtOH-lever responding but with potency differences. The time-dependent differences in EtOH-lever responding suggest that as solvents are cleared from the body, the EtOH-like subjective effects also fade.