use of platelet rich plasma had good effect in treating chronic wounds. healing of perianal fissure could be prolonged and associated with pain. injection of platelet rich plasma under fissure base and edges had the advantage of improved fissure healing and reduction of the pain, with minimal side effects.

Thirty milliliters of venous blood were withdrawn into eight syringes with preloaded 0.4 milliliters of anticoagulant (dextrose solution A) in each syringe to achieve concentration of 9:1.

The mixture centrifuged for 3000 round per minute for three minutes. After centrifugation separation of supernatant from the red blood cells, using three way-stopcock connector to collect the supernatant of all syringes into four new syringes that preloaded with 1 microgram of Prostaglandin E1 that diluted in normal saline (0.05 milliliters).

The four syringes centrifuge at 4000 round per minute for 15 minutes. The supernatant discarded using a three way-stopcock connector. The sediment mixed with vortex mixer (Vortex V-1 plus, BIOSAN).

Inclusion Criteria:

• chronic anal fissure for more than three months

Exclusion Criteria:

• medical comorbidity
• inflammatory bowel disease
• tuberculosis fissure
• HIV infected patients