Haemorrhoids are a weakening of the walls of the veins that serve the rectum and anus. These veins are put under pressure during a bowel movement, and, over time, they may lose their elasticity. When this happens, they bulge out from the muscle wall and cause complications. Increased pressure can come from vigorous straining while trying to pass stool. Pregnant women often experience haemorrhoids due to the increased pressure constantly placed on the pelvic floor by the combined weight of the fetus and amniotic fluid carried directly above the rectum during gestation. Hypertension, also known as high blood pressure, can also contribute to heamorrhoid formation.

Haemorrhoids can return to their normal dimensions without active intervention, but, once caused, the underlying conditions usually remain, and spontaneous reversal is uncommon. Under normal circumstances, patients treat their haemorrhoids symptomatically by apply steroidal or non-steroidal, anti-inflammatory creams. These creams reduce the localized swelling associated with haemorrhoids. External haemorrhoids often cause pain and itching around the anal area, and creams or suppositories can provide prompt relief.

External haemorrhoids occur outside the anal opening. The veins swell out from under the skin. They can be quite painful as the associated muscle tissue swells into shapes it was not designed to do. Because they are tender to the touch, proper hygiene becomes problematic. External haemorrhoids are tender and they can bleed when abraded by toilet paper. Wet wipes are recommended for thorough cleaning, and to prevent remaining fecal material to cause itching at the site.

Internal haemorrhoids are not associated with pain, since the rectum does not contain nerves that register pain. Copious, bright red bleeding is usually the first sign of internal haemorrhoids. This can be accompanied by straining while trying to pass stool, or it may lead to a feeling of rectal fullness because the haemorrhoid is taking up the space that feces normally would. 

Irregular bowel movements and diet have been linked to increased incidence of haemorrhoids. A diet high in fiber and containing plenty of fluids has been shown to promote bowel regularity. The muscles of the rectum and anus need exercise the same as any other muscle group, but they should not be subjected to undue strain. Large, soft, well-formed stools will provide these muscles with the appropriate exercise they require to keep their tone and resilience. A low fiber diet without plenty of fluids encourages slower bowel contractions and produces small, hard stools. These are difficult to pass, especially if a large internal haemorrhoid is blocking their path.

Without treatment, internal haemorrhoids can become prolapsed, meaning that they are pushed outside the rectum into the anal canal, sometimes to far as to be visible. These are the condition's most severe form.