For many years, it has been recognized that elevated serum cholesterol is a risk factor associated with atherosclerosis and coronary heart disease, the latter being a major cause of death in Western countries. Numerous drugs that lower cholesterol have been used to treat hypocholesterolemic individuals. However, the undesirable side effects of these compounds have caused concerns about their therapeutic use. Ingestion of probiotic (beneficial for health) lactic acid bacteria (LAB) would possibly be a more natural method to decrease serum cholesterol in humans, as has been was reported. Previous studies have demonstrated that Lactobacillus reuteri administered in low doses has a hypocholesterolemic effect both therapeutically and preventively. One of the key studies in the development of a probiotic is to determine the minimal effective dose of live microorganisms that might be ingested without producing adverse effects (i.e., translocation) in the host. In this chapter, we describe an animal model that allows us to evaluate reduction in hypercholesterolemia by LAB and, also to determine the minimal dose of the microorganism, a critical step in the development of a safe probiotic product.