This article is an analysis of the characteristics of exogenous endoscopy-related infections, pseudoinfections, and toxic reactions that have occurred worldwide during the period 1974 - 2004. A systematic review of the scientific literature published between 1966 and 2004 was conducted in Medline and the Food and Drug Administration Reports database, using a prospective protocol developed by the authors. The literature review identified 140 outbreaks, reported in 134 scientific articles. More than 94 % of the outbreaks identified could have been prevented by improved decontamination processes. Proper decontamination practices and the improvement of surveillance systems could reduce the clinical burden associated with exogenous endoscopy-related events.