The aim of this study is to determine the effects of an intervention using a commercially available probiotic in a cohort of acute stroke patients. In order to determine this, a double blinded, randomised and placebo-controlled study design was chosen.

Patients are recruited from the Stroke Unit of the Ludwig Maximilians University Munich within seven days of stroke onset. Recruited patients are then randomly assigned to either the Control or Treatment group and subsequently take the commercially available probiotic, or the placebo, twice a day for 3 months. At this point, study participants present themselves for routine clinical examination at the outpatient clinic of the Institute for Stroke and Dementia Research (ISD). During these examinations, blood and stool samples are collected for metabolomic and metagenomic analysis. Additionally, questionnaires concerning cognitive function (MOCA), depression (BDI) and general gastrointestinal status (GSRS-IBS) are completed.

Clinical data from both acute admission and three month follow-up are also collected for the purposes of this study.

Furthermore, members of the same household as the study participants are asked to donate a stool sample. These samples will be used to create a reference cohort for a paired matching approach with the Treatment and Control groups.

Inclusion Criteria:

• Diagnosis of ischemic stroke with onset in past 7 days
• Treatment received in the Stroke Unit of the LMU University Hospital, location Großhadern

Exclusion Criteria:

• Chronic immunological disease
• Severe gastrointestinal disease
• Colectomy
• Artificial intestinal outlet (ostomy)
• Liver cirrhosis, pancreatitis, gastritis, cholecystitis (or other acute gastrointestinal diseases)
• Chronic alcohol abuse
• Terminal prognosis