Imagine going to the bathroom for some bowel movement, and you see a stream of blood gushing out of your behind. That is a sight that not many can stomach. Yet, it is more common than you think. Bleeding hemorrhoids is considered one of the worst kinds of hemorrhoids, and it is advisable to consult a physician as bleeding from the anal area is not exclusive to hemorrhoids. It is also a sign of cancer and many other conditions.
Right, assuming that it is hemorrhoids this time, the main causes of bleeding hemorrhoids include a weak rectal vein walls and valves. Hemorrhoids induce pressure on these walls and valves, therefore, causing them to burst and bleed. Secondly, serious constipation would be another cause. As you are stressing your abdominal muscles to pass stool, what you are doing is increasing pressure on your anal region, therefore, causing the veins of the hemorrhoid to burst and bleed. Prolonged sitting and poor muscle tone and posture would also add pressure to the anal region. Therefore, also causing veins on the hemorrhoids to have increased pressure, thus bursting and bleeding.
Less direct causes of bleeding hemorrhoids would include excessive consumption of alcohol and caffeine. These properties increase the blood pressure throughout the body. Therefore, the weak veins on the hemorrhoid would not be able to withstand the increased pressure, thus, again, bursting and bleeding. Another cause would be pregnancy, as pregnancy does indeed increase straining of bowel movement and hypertension. Therefore, incurring stress on the veins on the hemorrhoid itself or in the anal region.