A grain of stool may be insufficient intake of water and other physiological factors and anal fissure, congenital megacolon and other pathological factors. 1. Physiological factors: insufficient water intake, daily dietary habits prefer cold, hard, spicy and stimulating foods, such as fried chicken, pickles, marinated meat, spicy hot, strong tea, etc., easy to aggravate the burden on the gastrointestinal tract, causing intestinal peristalsis slows down, resulting in constipation, abdominal pain, abdominal distension, loss of appetite and other symptoms. 2. Pathological factors: (1) Anal fissure: it refers to the rupture or tear of the skin of the anal canal, which is most commonly found in the posterior median part of the anal canal, and the direction is mostly parallel to the longitudinal axis of the anal canal, which is pike or oval in shape. Patients may be reluctant to defecate due to pain during defecation, resulting in dry stools and constipation. (2) Congenital megacolon: also known as “Hirschsprung’s disease”, is a common congenital malformation, caused by intestinal neuron deficiency, mostly in the sigmoid colon and rectum. The affected intestinal tubes are spasmodically narrowed, resulting in intestinal contents not being able to pass through and be discharged normally, causing persistent constipation and other manifestations. It is recommended to consult a doctor in time, under the guidance of the doctor to carry out targeted treatment.