There is no such thing as which three diseases may be responsible for hard head followed by soft stool. The symptoms of hard stool may be gastrointestinal obstruction, indigestion, irritable bowel syndrome and other diseases. 1. Gastrointestinal obstruction: poor intestinal function, intestinal environment disorders and other factors, stools accumulate in the intestines for a long time and can not be discharged in a timely manner. When the accumulation time is too long, the water may be absorbed and this situation occurs. 2. Indigestion: Long-term consumption of high-protein foods, foods with too little fiber content, etc., causes indigestion, constipation, and the phenomenon of hard stools followed by soft stools. 3. Irritable bowel syndrome: Gastrointestinal peristalsis is weakened, and the intestines are unable to properly transport intestinal contents, which affects defecation and leads to constipation, and hard and then soft stools. If the symptoms of hard stools are aggravated, it is recommended that the patient go to the gastroenterology department of the hospital in a timely manner, and under the guidance of the doctor for the next step in the examination and treatment.