Constipation is a common symptom of the digestive tract in which the frequency of bowel movements decreases, the volume of stool decreases, the stool is dry and strained to pass. Sudden constipation may be transient. But it can also be a sign of disease in some part of the body. There are often two causes of sudden constipation. Common organic causes include rectal-anal lesions, occupational lesions of the intestines, or side effects from medications such as iron or antidepressants. There are also neurological lesions, such as stroke and spinal cord injury; secondly, there are functional causes, such as irregular diet or consumption of spicy and irritating food leading to disorders of gastrointestinal function, work tension, fast pace of life, changes in the nature and timing of work, and mental factors that interfere with normal bowel habits. The weakness of the elderly, too little activity, intestinal spasm, etc. lead to difficulty in defecation. To sum up, for sudden constipation, you should go to the hospital for examination in time to clarify the cause and avoid ignoring the signals of some important diseases. If organic lesions are found, timely treatment should be carried out according to the needs of the condition. At the same time, one should avoid the use of some stimulating laxatives that cause further disorders of intestinal function.