Introduction: Surgical treatments for fissure overcome spasm of the IAS by forcible anal dilatation or internal 
sphincterotomy. Both anal dilatation and sphincterotomy are associated with short-term and long-term impairment of 
continence in up to 30% of patients. Glyceryl trinitrate (GTN) ointment applied to the anus causes a fall in maximum anal 
resting pressure (MARP) amounting to a reversible "chemical sphincterotomy". Oral and topical preparations of calcium 
channel blockers have recently shown to lower anal resting pressure probably by relaxing the internal anal sphincter. 
Patients and Methods: 120 patients presented with chronic anal fissure were randomly selected and classified into three groups. Group (1) used Glyceryl Trinitrate gel 0.25%, Group (II) used Nefidipine gel 0.5%. Group (III) were submitted for 
lateral sphincterotomy with or without fissurectomy. 
Results: Our results were assessed and compared in the 3 groups under the following points: time of pain relieve, healing time (Table 2), headache as a side effect of the therapy used, incidence of recurrence and comments of the patients included in our study. As regard complete healing of the fissure, this was recorded in 34 patients in GTN gp in a mean time of 28 days. While in NF gp, healing was recorded in 29 patients in a mean time of 33 days. In OP gp the healing was recorded in 34 patients in a mean time of 28 days. 
Conclusion: Both Glyceryl Trinitrate 0.25% and Nefidipine 0.5% are effective in treating chronic anal fissure when applied 
topically. Both harbor minimal side effects, excellent patient's compliance and good healing rate when compared with 
surgery. They can replace surgery in most of cases. No need for hospitalization with the result of saving money and time with preservation of the normal anal tone after healing. So, chemical sphincterotomy must be the first line in treatment of chronic anal fissure