C12H22O11 – lactose – is a carbohydrate similar to ordinary sugar. It is available in powdered form like regular sugar, but is not sweet enough for use as a culinary sweetener. Lactose is a component of milk and many dairy products; the word itself comes from “lac,” the Latin word for milk, plus the suffix -ose, indicative of a sugar. It is also called milk sugar. Lactose can be added to pharmaceutical drugs as a filler. It is also added to baby formulas and is the foundation of the human diet in the first years of life. Some people develop an intolerance to this sugar as they age.