Purpose: This randomized study assesses the effects of antibiotics on the formation of
fistulae after drainage of anorectal abscesses.
Methods: Patients who underwent abscess drainage in 3 major colorectal units between
September 2005 and January 2008 were included. Previous anorectal surgery history,
immunecompromised states, pregnancy, inflammatory bowel disease, antibiotic usage prior to
surgery and the presence of an anal fistulae at the time of surgery were the exclusion
criteria. Patients were randomized and given either placebo or amoxicillin-clavulanic acid
combination treatment for 10 days. Patients were followed one year for perianal fistulae
formation.