A series of unexplained deaths associated with soft-tissue inflammation and severe systemic sepsis was reported among injection drug users (IDUs) in the United Kingdom and the Republic of Ireland in 2000. Health Canada has identified one reported fatality in an IDU that matched the case definition. Although the cause of the epidemic in the UK and Ireland is not fully understood, contributing factors include injecting into muscle or beneath the skin, rather than directly into a vein, and the use of acid to dissolve the heroin. This single Canadian case is considered to be a sporadic event that occurs at a low background rate among IDUs. These cases serve to remind primary health care providers to be vigilant in cases of soft-tissue infection among IDUs and not to underestimate the potential severity of the situation.