Gastrointestinal diseases are becoming increasingly prevalent in the medical society today with approximately 60 to 70 million Americans affected by gastrointestinal diseases every year. One method of combatting these diseases is through the use of probiotics. Therefore, the aim of this presentation is to provide a review of the literature and a summary of what probiotics and yogurt are, how probiotics are selected, factors that influence the effectiveness of probiotics in yogurt, and how probiotics can benefit human health. A systematic literature research was conducted to further investigate this topic. Databases used included Google Scholar and the Journal of Dairy Science. One of the primary vectors for human consumption of probiotic is through fermented dairy products, especially yogurt. The bacteria of the genus Lactobacillus and Bifidobacterium are added to the yogurt either before or following fermentation and have been proven to positively affect gut health by improving the balance between beneficial and harmful bacteria. Although probiotics are not essential for survival, probiotics are highly recommended as they improve gut health, especially under conditions that decrease the normal microflora of the intestines, such as chronic and acute diseases, antibiotics, and age.