Serious infections with the "nonpathogenic" Bacillus species are increasingly being recognized, especially in drug abusers. Cases of panophthalmitis secondary to infection with Bacillus cereus, with and without associated bacteremia, have been reported. Three drug abusers with panophthalmitis seen in our hospitals during a three-year period are described, and the similar cases reported in the literature are reviewed. The syndrome is characterized by an acute onset with a rapid fulminating course that eventually leads to enucleation or evisceration of the eye. The pathogenic mechanism is unknown, but is probably related to the production of toxin (lecithinase) by B. cereus. Clindamycin appears to be the antibiotic of choice in the treatment of this infection. In order to identify a possible source of the organism, 59 samples of heroin and injection paraphernalia were cultured. Twenty cultures yielded organisms; Bacillus species were the predominant isolates. Thirty-eight percent of the isolates were identified as B. cereus. Thus, infections caused by Bacillus species in drug abusers can probably be associated with intravenous heroin abuse because heroin mixtures and injection paraphernalia are frequently contaminated with this organism.