Several previous studies have shown that Gastrografin can be utilized to triage patients with adhesive small bowel obstruction (ASBO) to an operative or a non-operative course. Previous studies assessing the therapeutic effect of Gastrografin have been confounded by post-administration radiology alerting the physician to the treatment group of the patient. Therefore the aim of the present paper was to test the hypothesis that Gastrografin hastens the non-operative resolution of (ASBO). Patients, diagnosed with ASBO on clinical and radiological grounds, were randomized to receive Gastrografin or placebo in a double-blinded fashion. Patients did not undergo further radiological investigation. If the patient required subsequent radiological intervention or surgical intervention they were excluded from the study. End-points were passage of time to resolution of ASBO (flatus and bowel motion), length of hospital stay and complications. Forty-five patients with ASBO were randomized to receive either Gastrografin or placebo. Two patients were excluded due to protocol violations. Four patients in each group required surgery. Eighteen of the remaining patients received Gastrografin and 17 received placebo. Patients who received Gastrografin had complete resolution of their ASBO significantly earlier than placebo patients (12 vs 21 h, P = 0.009) and this translated into a median of a 1-day saving in time in hospital (3 vs 4 days, P = 0.03). Gastrografin accelerates resolution of ASBO by a specific therapeutic effect.