Eikenella corrodens is a gram-negative, facultative rod-shaped anaerobe that colonizes the human mouth, nasopharynx, gut, and genitourinary tract. We treated a corneal ulcer from which E. corrodens was the primary isolate in an otherwise healthy man. We treated another patient who had recurrent bacterial endophthalmitis from which Eikenella was identified in mixed culture. Named for its ability to form pits in agar, the corroding bacillus is gaining recognition for its role in head and neck infections. Certain E. corrodens strains are mobile on moist surfaces and elaborate an endotoxin, which may destroy human tissues directly and indirectly by means of the immune system. The organism is usually resistant to aminoglycosides and penicillinase-resistant penicillins yet is susceptible to penicillin and some cephalosporins.