The immediate definitive operations for perforated peptic ulcer is never entirely safe. The present study was conducted on 20 patients presented with large perforated peptic ulcer and 10 dogs where large hole in their stomach was done 
experimentally. The patients and dogs were treated by omental plug technique. Twelve patients presented with perforated duodenal ulcer and 8 with gastric ulcer. In the applied part , the overall morbidity rate was 20%. The plug in the patients of perforated duodenal ulcer disappeared on the 4th postoperative day in 7 out of 12 patients but in perforated gastric ulcer disappeared on the 5th day in 6 out of 8 patients, there was neither re-perforation nor leakage. After 24 months of follow up for 18 patients , 4 patients (22.2%) were cured , 9 patients (50%) responded well to medical treatment and 5 patients (27.8%) continued to complain of ulcer symptoms and needed definitive surgery. After 8 weeks in experimental part, by gross examination the omental plug merged with the serosal surface of the stomach and the gastric hole disappeared without discontinuity of the mucosa and by histologic examination , few bundles of smooth muscle fibres were seen within the site of omental plug in all dogs. We conclude that, the omental plug technique is simple, excellent and life saving procedure but it has limited value to patient in terms of definitive cure.