Background and Aim Isolation measures in patients with acute diarrhea produce enormous costs of materials and personnel. Aim of this retrospective study was to evalute the percentage of unnecessary isolations and the impact of multiplex PCR stool testing on isolation days before and after introduction into clinical practice. Methods: Between July 2020 and July 2022 in total 2373 stool specimens of patients with acute diarrhea and a course no longer than 14 days were analyzed using BioFire® FilmArray® Gastrointestinal (GI) Panel. Number of isolation beds per day were compared before and after the introduction of Multiplex PCR testing. Results: In 65% of all specimen examined no pathogen was detected. Single-room isolation was a necessary in only 22% of all cases. Isolation days on the gastroenterological ward decreased from 635 in 2019 to 384 in 2020, a reduction of 39,5%. Conclusion: In acute infectious diarrhea Multiplex PCR is a use full tool to rapidly identify the causative agent and exclude the necessity of isolation in the majority of cases. In spite of all medical and economical advantages Multiplex PCR testing has not been established widely so far.