Iranian trial on functional abdominal pain in children, with the use of L. reuteri DSM 17938. There were no differences between L. reuteri and placebo groups for frequency and severity of abdominal pain. Study population seems biased compared to previously published studies on effects of L. reuteri DSM 17938.
Link to study article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4662837/
Eftekhari K, Vahedi Z, Kamali Aghdam M, Noemi Diaz D. A randomized double-blind placebo-controlled trial of Lactobacillus reuteri for chronic functional abdominal pain in children. Iran J Pediatr. 2015;25(6):e2616.