delta-9-Tetrahydrocannabinol (THC) kinetics and dynamics of self-reported psychologic "high" effect are analyzed in six subjects who smoked marijuana cigarettes of three different potencies. Correlation of the pharmacologic response to smoking a marijuana cigarette with plasma THC levels was done with compartmental models and phase plots. It was concluded that the effect compartment for psychologic high is directly coupled to the central (plasma) compartment. It was observed that effect is directly proportional to mean THC levels from approximately 1 to 4 hr after the start of smoking a marijuana cigarette.