Comparative Evaluation of MEBO Ointment and Topical Diltiazem Ointment in the Treatment of Acute Anal Fissure

Inclusion Criteria: * Subjects must be 18 years and above. * Subjects with 3 months (90 days) or less history of painful anal fissure (AF), prior to screening, where AF-related pain-associated with, or following, defecation is experienced at least twice a week during the symptomatic phase, with pain scores at an average of ≥ 3 on an 11-point NRS (Numerical Rating Scale, range 0-10 where 0 = no pain and 10 = worst pain imaginable). * Subjects with an average of ≥4 on an 11-point NRS during the screening phase for worst anal pain associated with, or following, defecation for the most recent 3 days on which the subject has defecated. * Subjects with evidence of a radial fissure, with induration at the edges, seen on anal examination. * Willing to stop all other concomitant topical preparations applied perianally prior to commencing study treatment, and throughout the study. There will be a "washout" period of at least 2 weeks prior to commencing the study for subjects who were using other concomitant topical preparations applied perianally. * Able to give consent Exclusion Criteria: * Subjects unwilling to be examined for AF. * Subjects who have undergone the following procedures: * Lateral sphincterotomy or anal stretch or other previous surgery involving the anal canal or perianal region (hemorrhoidectomy, anal fistula surgery). * Incision of perianal abcess. * Subjects who have had sub-fissure injection of botulinum toxin within 6 months period prior to screening, or have used glyceryl trinitrate (GTN) ointment for \>1 week in the 4 weeks prior to the screening visit. * Subjects with AF associated with other conditions (drug-induced \[e.g. nicorandil\], trauma, HIV infection, fistula-in-ano, inflammatory bowel disease, perianal sepsis or malignancy). * Subjects with cardiovascular disease * Subjects with known hypersensitivity to DTZ or the ingredients of MEBO (Sesame oil) * Subjects taking medications prohibited by the protocol. * Subjects who have taken experimental agents must have been discontinued at least 8 weeks prior to screening, or for a period equivalent to 5 half-lives (t1/2) of the agents. * Subjects who have the following gastrointestinal disorders: * Inflammatory bowel disease. * Chronic faecal incontinence. * History of radiation therapy to the pelvis. * Fixed anal stenosis/fibrosis. * Subjects with major psychiatric (including drug or alcohol abusers), or haematological illness. (diseases of the vascular system; source: )Subjects with planned elective or other treatment requiring hospitalization, during the study, booked before entry into the study. * Subjects who will be unavailable for the duration of the trial, likely to be noncompliant with the protocol, or who are felt to be unsuitable by the Investigator for any other reason. * Patients who are taking oral therapy for anal fissure will also be excluded from the study.