The main common causes of anal itching after a bowel movement include fecal irritation, perianal eczema or parasites. There may also be fungal infections, simple anal pruritus ani, etc., caused by perianal malnutrition or leukoplakia. 1. Fecal stimulation: after defecation, some patients have residual feces in the folds of the anus, which is easy to cause skin irritation, and patients are often accompanied by anal itching and other uncomfortable symptoms. 2. Perianal eczema: patients with previous perianal eczema disease, local skin sensitivity, stool will aggravate the stimulation of the skin, further aggravate the itching symptoms. 3. Parasitic diseases: patients infected with roundworm and other parasitic diseases, especially pediatric patients, after defecation, part of the parasites remain in the anus, the patient is often accompanied by itching symptoms. Patients with anal itching after defecation and other discomforts, may also be associated with fungal infections, simple anal pruritis, perianal malnutrition or leukoplakia and other lesions, the specific causes need to be further examination, differential diagnosis. It is recommended that patients should seek timely medical treatment to avoid aggravation of the condition.