If the exhaust is particularly foul smelling, we often consider whether there has been recent indigestion. It depends on whether you have recently eaten something spicy, irritating, fried, too hard, etc. that causes indigestion. In addition to this smelly gas, are there any bloating, flatulence, abdominal pain, or stomach pain, and any changes in bowel movements? If these conditions are present at the same time, you may consider that you have not eaten well recently, which may cause indigestion or other gastrointestinal diseases, and you may consider having a gastroscopy or colonoscopy. If there is no pain symptoms, it may be caused by gastrointestinal dysfunction, indigestion. You can take medicines and foods to promote gastric digestion, then eat a light diet, drink more water, and see if there is any improvement after adjustment.