A Randomised Controlled Trial of the Use of Topical Metronidazole (10%) to Reduce Pain After Haemorrhoidectomy

Inclusion Criteria: * Have Grade 3 or 4 haemorrhoids (external disease with or without significant internal component) * Be scheduled for diathermy haemorroidectomy with ≥2 quadrant involvement * Be medically fit for surgery * Subjects must be aged 18 years or over and of the legal age of consent. * If female, the subject must not be lactating and must be (a) post-menopausal, (b) surgically sterilised, or (c) have a negative pregnancy test result prior to entry into the study and will use adequate contraception for the duration of the study. * Must have provided written informed consent to participate. Exclusion Criteria: * They have had surgery to the anus or rectum in the past 8 weeks * Suffer from a chronic pain syndrome which requires regular narcotic analgesia * Have anal fissures * Have diagnosed Crohn's disease * Allergic to metronidazole * Are taking any prohibited medication. * Deemed mentally incompetent * Considered by their physician unlikely to be able to comply with the protocol. * Taken part in an experimental drug study in the preceding three months.