Abstract: The invention relates to a method and device for the investigation of sludge deposition on materials for coating endoprostheses. At least one endoprosthesis is placed in an incubation chamber which is at least partly filled with infected bile. The incubation chamber is rocked gently on a rocking platform for a period of about 35 days. The bile fluid is regularly partly exchanged. The endoprosthesis is embodied in a coated plastic. The coating comprises 70 to 80% by weight of hydrophobic components and 30% to 20% by weight of hydrophilic components. The coating may particularly have a sol-gel embodiment. An application in bile duct prostheses is possible.