No one knows for sure when yogurt first appeared on the culinary scene, but estimations date its arrival back to the beginning of agriculture. The first record of possible health benefits from yogurt was in the 1500s. The Sultan of the Ottoman Empire sent his doctor with a satchel of yogurt to Francois I, the King of France, to cure his intestinal disorder. It worked and yogurt's reputation as a health food was born. Soon after, people began praising the health benefits of yogurt by claiming it cured many different illnesses.

Yogurt is made from milk—whole, low-fat, or skim milk can be used. Live bacteria, also known as cultures, are added to the milk. Lactobacillus bulgaricus and Streptococcus thermophilus are the two cultures required for a product to meet the legal definition of yogurt. Some manufacturers add other bacteria as well. The mixture is then incubated—time and temperature will determine the flavor, consistency, and acidity.

The bacteria in yogurt are commonly known as probiotics or friendly bacteria. Studies suggest that these probiotics can provide a variety of benefits, including preventing traveler's diarrhea, antibiotic-associated diarrhea, and other forms of digestive infection, and possibly strengthening the immune system against respiratory infections.