Human cells grown in culture have an absolute requirement for choline, and humans sustained by choline-free parenteral solutions develop symptoms similar to those of the deficient rat. It is on this basis that the inclusion of choline in a list of “conditionally” essential nutrients is argued. Choline is the trivial name for 2-hydroxy-N,N,N-trimethyl-ethanaminium. Choline is freely soluble in water and ethanol but insoluble in organic solvents such as ether or chloroform. It is extremely hygroscopic. It is a strong base and readily decomposes in alkaline solutions, resulting in the production of trimethylamine. Because of its unique structure, choline serves as a donor of methyl groups. Choline is widely distributed in foods and is consumed mainly in the form of lecithin. Lecithin is not only a naturally occurring common food ingredient but is also a common additive to processed foods. It serves as a good food stabilizer and emulsifying agent.