Symptoms of gastric cancer, especially in the early stages, generally include nausea, vomiting, loss of appetite, discomfort or bloating in the upper abdomen, pain, and acid reflux as some of the gastrointestinal symptoms, as well as vomiting blood and black stools. Black stools are tar-like stools, and their occurrence indicates bleeding in the upper gastrointestinal tract. Additionally, if the tumor causes pyloric obstruction, the patient will vomit food eaten the night before, be completely unable to eat, and experience a significant weight loss. In even more advanced stages, gastric cancer patients may develop a cachectic state.