 Despite the widespread use of THC in clinical practice, there are few studies on the efficacy of THC In a double-blind, randomized trial. In addition, few studies examined the effect of THC on the experience pain in healthy subjects and most of them did not find an effect on pain experimental induced by capsain. so checking other models of pain such as thermal pain and mechanical pain in addition to checking the influence on the regulation of pain will contribute to understanding the mechanism of action of THC. Understanding the mechanism of action of THC in relieving pain will lead to predicting who will benefit from this treatment and direct patients for selection of appropriate medication according to the damaged mechanism. 