What to do for an anal fissure with constipation?

Softer stool. Treatment for fissure requires making sure stools are soft and bulky as well as use of a topic vasodilator ointment applied to the anus.
Soften the stools. Anal (or rectal) fissures are usually caused by passing a large stool. As the rectum stretches to allow passage of the large stool, small tears or fissures can occur. These tears can hurt and lead to small amounts of blood on the stool or toilet paper. The goal is to have smaller, softer stools by increasing the amount of fluid and fiber in the diet. A mild bulk laxative may also help.