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. Hemorrhoids are often caused by straining during a bowel movement. Some ways to prevent hemorrhoids include emptying your bowels as soon as possible after the urge occurs and keeping stools soft -- by increasing fiber in the diet and exercising -- so that they pass easily.