<qa>  What is the aim of the study?The aim of the study is to evaluate the soluble biomarker syndecan-1 sSdc1 taken from venous blood of patients with infectious intestinal diseases such as Clostridium difficile-associated colitis, bacterial colitis, Norovirus enteritis and Crohn s disease or ulcerative colitis. The level of sSdc1 will be compared with disease activity in patients with active inflammation and with disease in remission. Secondary objectives were the assessment of correlation of the above-mentioned factors with the CRP value. Subjects will be volunteers. Blood will be taken as part of the routine clinical work-up after the written agreement blood and sSdc1-level will be assessed using a human-specific sSdc1 ELISA assay. In addition, the subjects are asked to answer a short questionnaire. The study is designed as a prospective, comparative cohort study. 