My grown son has a horrible smelling belch from time to time. He also has been to the ER with sever stomach pains, bloating, diarrhea one minute and then constipated the next, and he has thrown up. All tests on gallbladder, pancreas, appendix, stomach, and spleen have come back fine. He has had numerous xrays, ultrasounds, and an upper GI. Someone suggested he could have intestinal parasites or h. pylori. any comments?