In early stage of gastric cancer, there is often only mild nausea and feeling of fullness. 3.9% of gastric cancer patients visit the doctor with vomiting as the first symptom, while vomiting is more common in middle and late stage of gastric cancer. Vomiting is mainly related to the location of gastric cancer. Gastric cancer occurring in the sinus and near the pylorus can easily cause pyloric obstruction, which can obstruct the emptying of food and lead to gastric dilatation, and then cause vomiting, and the vomit is mostly overnight food that has stayed in the stomach for too long and has a corrupt and sour smell. When gastric cancer occurs at the bottom of the stomach and invades the lower part of the esophagus, this symptom will appear, which only occurs when eating hard food at the beginning, but later it will also occur when eating soft food. This symptom is not only seen in gastric cancer, but also in esophageal cancer. Therefore, anyone who has the feeling of obstruction in the lower throat should have a barium x-ray or esophageal (gastroscopy) examination in time to avoid delaying the diagnosis.