ANAL FISSURE:
Definition: a split in the tissues of the anus, called an anal fissure. 
This may be due to constipation, or chronic anal irritation.  The
fissure causes pain during bowel movements.  It may bleed when you pass
stool.  Treat the fissure with warm sitz baths three or four times a
day.  Clean the anal area carefully -- special cleansing pads (Tucks)
may be helpful.  Sometimes prescription suppositories are helpful in
reducing pain and inflammation.  A stool softener (such as metamucil)
will make bowel movements less traumatic.  Eat a diet high in fiber
(fruits, grains), and drink plenty of water.  See your doctor if there
is profuse bleeding, increasing pain, an enlarging mass, or fever -- or
if the symptoms do not resolve after treatment.