Octylonium bromide (OB) is a drug with spasmolytic properties acting selectively on the smooth muscle of the gastrointestinal tract by interfering with calcium mobilization from extra- and intra-cellular deposits. The etiopathogenetic implications of a psychosomatic nature of the irritable bowel syndrome amply justify the use of a spasmolytic (OB) with a benzodiazepine. In our study, we compared the combination OB + DZ (20 mg + 2 mg) T.I.D. versus OB alone (20 mg) in 30 patients suffering from irritable bowel syndrome. The double-blind study lasting 3 weeks was aimed at evaluating gastrointestinal symptoms (bowel motions, aspect of faeces, abdominal pain, pre-evacuation pain, bloating) during the three days preceding the study and during the last five days of treatment, as well as the anxiogenic situation as assessed by the STAI scale (State Tract Anxiety Inventory) before and at the end of the treatment period. The results obtained showed that both treatments considerably reduced gastrointestinal symptoms even though OB alone did not appear to be equally effective and the anxiety component was significantly reduced only by treatment with the combination. The absence of side effects and the perfect tolerability of both treatments showed the OB + D combination T.I.D. to be the treatment of choice for patients suffering from irritable bowel syndrome.