Graft versus host disease (GVHD) is one of the major causes of death in patients undergoing allogeneic hematopoietic cell transplantation. Despite prophylactic measures, the incidence of acute GVHD is estimated at 40-60% among patients receiving transplant from HLA-identical sibling donors, and may even reach 75% in patients receiving HLA-matched unrelated transplants. More effective prevention and treatment strategies are needed.

The immunomodulatory and anti-inflammatory properties of Cannabinoids have been shown in animal models of various inflammatory diseases including multiple sclerosis, inflammatory bowel disease and rheumatoid arthritis.

Cannabidiol is a major non-psychoactive cannabinoid, which has potent anti-inflammatory and immunosuppressive effects.

As such, it may reduce the incidence and severity of GVHD after allogeneic stem cell transplantation.

Inclusion Criteria:

1. Patients undergoing allogeneic stem cell transplantation.
2. No previous history of psychosis. -

Exclusion Criteria:

1. Previous history of psychosis.
2. Consumption of cannabis during the last 2 moths before transplantation. -