The intestinal mucosa is not typically exposed to gastric acid, which is neutralized by the alkaline biliopancreatic secretions. The jejunal mucosa has no natural barriers; when exposed to gastric acid, it ulcerates easily. Capella & Capella demonstrated that transecting the gastric segments significantly reduce staple-line dehiscence; this is the so-called divided gastric bypass. In the retrospective analysis of their consecutive series, the incidence for gastro-gastric fistula (GGF) formation after undivided gastric bypass (GBP) was 23%, after a partially divided GBP was 19%, after a completely divided GBP was 2% and after complete transection with interposition of the jejunal limb was 0% (p <0.001). MacLean et al confirmed that divided primary gastric bypass decreases GGF formation (29% vs. 3%). Also, patients who developed marginal ulcers had a lower pH as well as a greater time with a pH less than 2 correlating 100% with the presence of GGF; closure of the GGF increased the pH in the pouch with subsequent healing of the marginal ulcer.