In 21st century medicine, nosocomial infections still represent a common treatment risk. The author systematically explains the diverse requirements for a standard infection-preventive hygiene organisation in medical institutions and analyses the associated civil law and, in particular, criminal law liability risks. Both the requirements of § 23 of the Infektionsschutzgesetz and the obligation of medical facilities to inform patients about facility-specific increased infection risks exert considerable influence on questions of evidence under liability law. The author pays particular attention to the responsibility of clinic manager.