While gastric bypass surgery can be a great tool for significant weight loss and a real change in the lives of those who undergo it, it in not without dangers. There are several significant gastric bypass surgery risk factors that anyone considering the surgery should be aware of. Aside from the typical risks of ay major surgery, specific risks include dehydration, a bleeding stomach ulcer, vitamin and mineral deficiency, low blood sugar, and gallstones. Be sure to weigh all these risks before surgery. It is a good idea to have a plan of action before the surgery should any of these problems become a factor.