Modulating the microbiota of the gastrointestinal tract through probiotics is an alternative to the conventional treatment of various diseases, based on synthetic drugs. The lifestyle, nutrition and stress of the present modern society could be among the factors responsible for modifications in the intestinal microbiota, correlated with specific diseases. The present study describes the positive effects of probiotics use, with special reference to the yeasts use in several frequently encountered diseases, such as hypercholesterolemia, the irritable bowel syndrome, gastritis and several uro-genital disorders.