HEMORRHOIDS: WHAT CAUSES THEM? Hemorrhoids are almost always caused by an increase in pressure in the lower rectum.
The next logical question then is...
what causes the increase in pressure? There's not a simple answer to that question because there are so many factors that can contribute to increased pressure in the rectum and around the anus.
To name a few:

• chronic constipation: as the world "chronic" implies, this is an on-going situation that just never seems to get resolved.
  Bowel movements stay in the colon too long and become dry and hard resulting in stretching and scratching of the vessel walls and consequent bleeding.
  
• chronic diarrhea: the vessels of the rectum can also be damaged by frequent liquid stools.
  
• straining with bowel movements: Can rupture vessels as well as lead to hemorrhoids because of increased pressure.
  
• sitting on the toilet for too long.
  Sometimes people sit too long because of diarrhea or constipation or just dawdling on the toilet while reading.
  Bad idea! Way too much pressure on the vessels.
  
• pregnancy and labor: the weight of the developing baby increases the pressure on the veins in the rectum.
  A difficult or strenuous labor can also irritate the vessels.
  
• obesity: extra weight, especially in the abdomen, increases pressure on rectal veins (just like pregnancy).
  
• aging: because muscular support weakens throughout the body including those muscles that keep the rectal veins strong and healthy.
  
• heredity.
  One does not actually inherit hemorrhoids.
  However, one can inherit weak rectal vein walls which are easily traumatized by many of the other factors in this list
• sedentary life style: blood circulation is impaired when we sit too long.
  
• ignoring signals that the bowel is full: the body is made to signal us when it is time to empty the bowel.
  If we ignore that call, the stool sits in the colon where it becomes hard, dry,and difficult to evacuate without straining.
  
• rushing which often means straining: straining is bad whatever the reason.
  
• heavy lifting: The natural thing to do when lifting something heavy is to hold the breath and even grunt.
  This increases pressure in the entire abdomen, including the vessels of the rectum.
  
• excessive hard coughing: this causes the same increased abdominal pressure as heavy lifting.
  
• low fluid intake: The bowel needs plenty of fluid in order to keep the stool soft and moist.
  Hard, dry stools scratch or even cut the rectal veins.
  
• low fiber diet.
  Diets that are heavy in refined flour, sugar, meat, over-processed foods do not provide the bulk that is needed to move the stool through the bowel in a timely fashion.