Hemorrhoids are common colon problems that affect both men and women equally. They can be internal (inside the anus) or external (under the skin around the anus), and occur when the veins around the anus or lower rectum become swollen and inflamed. They are often caused by straining when having a bowel movement. Therefore, the best way to prevent hemorrhoids is to keep stools soft so that they pass easily and to empty your bowels as soon as possible after the urge occurs.