What causes constipation, gas and blood after bowel movement?

Various causes: The blood and gas are very likely caused by the constipation. Hard tools can abraid the rectal lining, causing bleeding. The causes of constipation vary, including dehydration, food devoid of fiber, psychological factors, inactivity, and in some cases disorder of the smooth muscle and nerves that serve the colon. Eat oatmeal for most breakfasts and take an apple a day to keep the doctor away.

Get colonoscopy: Hemorrhoids diverticulitis, colon cancer, ulcerative colitis, crohn's disease. You need to see a GI doctor and have rectal exam, and probably colonoscopy.

Several things.: If the blood is bright red and just a bit on the toilet paper or in the bowl when having a bm, it is due to a hemorrhoid or anal fissure (small tear). These occur with chronic constipation, contributors to constipation are niot enough water or fiber in the diet, or prolonged sitting. If the blood is dark, or heavy, go see a doctor. Otherwise work on improving your diet, fluids and exercise.