Now, you might think it's a stroke of bad luck that your digestive tract is an ideal place for pathogens. In fact, the alimentary canal needs to support micoorganisms, because we depend on some of them in our daily digestive processes. They help break food into its components to supply energy or build our bodies. It's an arrangement that benefits both the microbes and us.
Problems arise when pathogenic organisms find their way to the same hospitable enrivonment.