These are prominent blood vessels in the lower rectum and upper anal canal. The main symptoms are bleeding and prolapse (where the haemorrhoid protrudes from the anus). Haemorrhoids are usually painless, but there may be discomfort if they prolapse. They are often associated with skin tags, which are areas of stretched skin on the outside of the anus. The presence of severe pain and an external lump may indicate a clot in an external vein (referred to as a perianal thrombosis or perianal haematoma). Haemorrhoids are very common in the general population. They are more likely to develop in people who strain to empty the rectum or who spend a long time on the toilet. They are also common in pregnancy and after childbirth. Many patients with haemorrhoids can be managed without surgery, particularly by maintaining a normal bowel habit. Rubber band ligation is effective in certain patients and this is a minor procedure which can be performed in the office in some cases. More significant haemorrhoids may require surgical treatment such as haemorrhoidectomy.