BACKGROUND: The marijuana plant cannabis is known to have therapeutic effects, including improvement of inflammatory processes. However, no report of patients using cannabis for Crohn's disease (CD) was ever published. OBJECTIVES: To describe the effects of cannabis use in patients suffering from CD. METHODS: In this retrospective observational study we examined disease activity, use of medication, need for surgery, and hospitalization before and after cannabis use in 30 patients (26 males) with CD. Disease activity was assessed by the Harvey Bradshaw index for Crohn's disease. RESULTS: Of the 30 patients 21 improved significantly after treatment with cannabis. The average Harvey Bradshaw index improved from...