Effective treatment of acute pain, chronic and persistent is the most important concern in the world today. Although a variety of pain medications including anti-inflammatory painkillers and opiouids, patients continue to suffer from pain constantly. For over a century ,International committees studied the issue of cannabis, and almost uniformly recommended the use of cannabis for various medical applications ,especially those that include pain treatment.

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.

Inclusion Criteria:

A. Men aged 25-65. B. Were not treated with formulation contains Cannabis C. Can sign an informed consent form. D. Patients have a medical history that supports severe neuropathic pain over Three months And do not respond to other painkillers or suffer from side effects resulting from the use them E. At least moderate pain (more than 40 on a scale of 0-100 visual analogue scale). F. Did not receive epidural injection or invasive treatment in The last month before the entry to study . G. Not drinking alcohol or consuming high concentrations of opioid and Benzodiazifinim over 24 Hours before the experiment (equivalent to 40 mg morphine).

Exclusion Criteria:

A. Patients that found with serious level of anxiety in Patient Health Questionnaire (PHQ-9) . (These patients will be recommended by a doctor appointment with a psychiatrist). B.Patients with psychiatric problems or a family history of psychiatric disorders.

C.Patients with known cardiovascular problems D.Patients with neurological problems from a central source E.Patients taking blood pressure medication F.Patients who are unable to understand and follow the instruction of the study.

G.Diffuse pain syndromes from uncertain origin (like fibromyalgia) H.Alcoholism or chronic use of drugs. I.Malignant