Introduction: Pain is almost persistent symptom in patients with chronic anal fissure. Local anesthetics are commonly used in the management of those patients. Studying the effect of the local anesthetic its effect could help understanding the different physiological factors contributing to the disease, using anorectal manometry which provides objective assessment not only of sphincteric functions but also rectal functions & recto-anal interaction.Aim of the study: To study the different manometric data of patients with chronic anal fissure before and after the application of local anesthetics. Such study aims at studying the role of such commonly used medication which may throw the light on the pathophysiology of this disorder and create new perspectives regarding the management. All of this will deepen the insight towards better understanding of the anorectal physiology.Methods: Twenty Patients with chronic anal fissure, attending Kasr Al-Ainy outpatient clinic were included in this study. Patients associated with other specific anal pathology, previous anal surgery or any neurological disorders affecting pain perception were excluded from this study. The anorectal manometry was done before and after topical application of local anesthetic, its effects are measured by visual analogue pain scale.Results: History of incontinence (with varying degrees) in many of our studied patients raise the importance of anorectal physiology studies in the management and decision making even in simple anorectal disorders. Regarding the manometry results, there was significant decrease in resting anal pressures. However, anal squeeze pressures and endurance squeeze pressures were significantly higher. Rectal pressure during the defecation trial increased significantly, indicating improvement in the defecation process. The threshold volumes for initiation of different rectal sensations (constant sensation, first urge, maximal tolerable volume) were also significantly higher. Not only increasing the rectal capacity, but also decreasing the rectal pressures during urgency, improving significantly overall rectal compliance.Conclusion: The effect of anal pain extends from just symptomatic discomfort to affect the highly integrated ano-rectum segment both in continence and defecation. This can only be explained by the high integration and interaction between the anal canal and the rectum. This subject is under further research in the colorectal research unit.