Lactose

Lactose is a form of sugar and carbohydrate that was found in milk. It consists of galactose and glucose.

Milk was often used as a home remedy for insomnia, as the amino acid in the heated lactose was believed to act as a natural sedative.

Captain Jean-Luc Picard's aunt Adele had a recipe for a steamed hot milk toddy, which Picard shared with Doctor Crusher. She in turn prescribed one to Commander Riker, explaining that the lactose in the beverage would help him sleep better.