Lactobacillus: A bacterium normally found in the mouth, intestinal tract, and vagina. Lactobacillus can also live in fermenting products, such as yogurt. Humans appear to have a symbiotic relationship with this bacteria: some types have become an important part of food digestion, although Lactobacillus can also contribute to cavities in the teeth if allowed to remain too long within the mouth.
Quick GuideFat-Burning Foods in Pictures: Blueberries, Green Tea, and More
Subscribe to MedicineNet's Weight Loss/Healthy Living Newsletter
Nutrition and Healthy Eating Resources
Last Editorial Review: 3/19/2012