Three synthetic hallucinogens—DIPT, 5-MeO-DET, and 5-MeO-AMT—produced behavioral effects in rats similar to those of known abused hallucinogens like LSD and DMT, but not to psychostimulants like cocaine or methamphetamine. DIPT fully substituted for DMT and DOM, while 5-MeO-DET fully substituted for DMT; none fully substituted for cocaine or methamphetamine. All three compounds acted at serotonin 5-HT(1A) and 5-HT(2A) receptors and blocked serotonin reuptake. 5-MeO-AMT also weakly released serotonin and blocked dopamine uptake. DIPT and 5-MeO-DET may have abuse liability similar to hallucinogens and were hazardous at high doses, causing activity and lethality.