Rectal perforations due to topical treatments (enemas or foams) are unusual complications and they have been mostly reported in the use of barium enemas or in elderly patients with constipation. Very little has been reported about perforations secondary to topical treatment in patients with ulcerative colitis. We present the case of a patient with ulcerative colitis who suffered a rectal perforation complicated with a superinfected collection after the application of topical mesalazine foam.