Damp heat in the colon and anal swelling may be caused by perianal abscess, inflammatory bowel disease, hemorrhoids and other causes. 1. Perianal abscess: acute suppurative infectious disease occurring around the anus, anal canal and rectum. It is a bacterial infection, also known as perianal rectal abscess. The opening of the anal sinus is upward and pocket-shaped. The retention of fecal matter predisposes to sinusitis. The infection extends to the anal glands located in the sphincter space and leads to intermuscular infection. 2. Inflammatory bowel disease: including ulcerative colitis, Crohn’s disease. The former active colon mucosa in the lamina propria of diffuse neutrophils, lymphocytes, plasma cells and other infiltration, can be seen mucosal erosion. The latter is mainly a chronic inflammatory granulomatous disease, the lesion mucosa was longitudinal ulceration. 3. Hemorrhoids: pathological hypertrophy of the anal cushion at the lower end of the rectum. It can be divided into internal hemorrhoids, external hemorrhoids and mixed hemorrhoids. Internal hemorrhoids due to the anal cushion of the support structure, venous plexus and arteriovenous anastomosis branch pathological changes. The result is a congested, hyperplastic and enlarged anal cushion. External hemorrhoids are due to pathological expansion of the subcutaneous venous plexus distal to the dentate line. As well as connective tissue hyperplasia formation. If there is intestinal dampness and heat, anal swelling, do not use drugs on your own, you need to consult a doctor as soon as possible to avoid delaying the condition.