BackgroundDespite the existing evidence, many physicians are reluctant to use opioid analgesia for acute abdominal pain.MethodsWe performed updated conventional and network meta-analyses. For the first time to our knowledge, direct and indirect evidence of any type of opioid analgesia was estimated and compared using network meta-analysis.ResultsThere was no significant difference in the intensity of pain between the two cohorts (mean difference (MD) = 0.43 (-0.05 to 0.91), P = 0.08). In addition, no significant difference was detected in the rate of incorrect diagnoses between the opioid analgesia and the placebo cohorts (odds ratio (OR) = 0.79 (0.54 to 1.17), P = 0.24). Network meta-analysis demonstrated that the results of direct evidence of head-to-head comparisons of opioid analgesics with placebo were in accordance with the results of conventional meta-analysis. Moreover, estimation and comparison of the indirect evidence on the four opioid analgesics did not demonstrate significant differences in effect size.ConclusionsAny type of opioid analgesic can be used safely for acute abdominal pain without risk of impairment of diagnostic accuracy.