Parkinson's disease (PD) is an etiologically heterogeneous disorder. Experimental, clinical 'and epidemiological data suggest that intestinal inflammation contributes to the pathogenesis of PD. This article reviews recent literature on gut microbiota and intestinal inflammation in PD. We propose that intestinal inflammation links environmental factors (e.g. an altered gut microbiota composition) to neurodegeneration in (genetically susceptible) PD patients. In addition, there is an epidemiological and genetic overlap between PD and inflammatory bowel disease. This overlap provides an opportunity to develop new treatment strategies for at least a subgroup of PD patients.