In epidemiological, clinical and experimental studies, Tobacco has been identified as a major risk factor for peptic ulcer disease (PUD). Smoking carries an overall relative risk of 2.2 for developing PUD. A synergistic relationship for developing PUD exists between H pylori infection and smoking (2.3 vs. 6.1). Biological evidence suggests that smoking compromises the gastric mucosa barrier, decreases gastric emptying and increases gastric secretion. For marginal ulcer after RYGB, there are three cohort studies that showed positive correlation between smoking with developing anastomotic ulcer.