What are the early symptoms of intestinal obstruction? For intestinal obstruction, the symptoms that appear in the early stages vary depending on the location of the obstruction. If it is a high-level obstruction, the main early symptoms are nausea and vomiting. If it is a low-level obstruction, abdominal distension is more prominent early on, and nausea and vomiting are less common. Additionally, the cause of the obstruction also leads to different symptoms. For instance, if the obstruction is simply due to adhesions in the abdominal cavity, the early symptoms may include poor appetite or nausea and vomiting. If it is caused by tumors in the digestive tract, early symptoms might include abdominal bloating, difficulty defecating, bloody stools, or changes in the characteristics of the stool, among others.