Burning when you poop is usually caused by irritation or injury around the anus or lower rectum. Common causes include an anal fissure, which is a small tear that can cause sharp pain during a bowel movement and burning afterward, or hemorrhoids, which can cause pain, itching, swelling, and discomfort.
Hard stools, straining, constipation, diarrhea, sitting on the toilet too long, and a low-fiber diet can all make the area more irritated. Proctitis, which is inflammation of the rectum, can also cause rectal pain, bleeding, cramping, diarrhea or constipation, and a strong urge to pass stool.
You should pay attention to symptoms such as bright red blood, pain that lasts for hours after pooping, discharge, frequent diarrhea, or a feeling that you still need to go after a bowel movement. Burning that happens once may improve with softer stools, more fluids, and avoiding straining, but repeated or severe symptoms should be checked.
Do not self-medicate with creams, laxatives, or pain relievers for more than a short time without medical advice. See a gastroenterologist or colorectal specialist if the burning is frequent, severe, or comes with bleeding.