Ezzat, Shahira MSalem, Mohamed AElMahdy, Nihal MMahfouz, Marwa M2022-10-022022-10-022022978-012819096-810.1016/B978-0-12-819096-8.00060-4http://repository.msa.edu.eg/xmlui/handle/123456789/5198ScopusLecithin or phosphatidylcholine is a phospholipid that is a main constituent of the cell membranes of all living cells. Lecithin is a natural emulsifier produced by plants, animals and human body as a component of the bile juice to aid in fat digestion. It has many health benefits for the liver, gastrointestinal tract and the cardiovascular system. Lecithin is a precursor for choline so it works through increasing the synthesis, release and availability of acetylcholine, thus it helps in improving the brain’s functions and memory especially in Alzheimer’s patients, in addition to its antioxidant activity. In this chapter we will have an overview about the source, chemistry, health benefits of lecithin as well as its mechanism of action and pharmacokinetics. © 2022 Elsevier Inc. All rights reserved.en-USAntioxidantsChemistryPhosphatidylcholinePro-oxidantsSynthesisLecithinEffects in Health: The Bright and the Dark SideArticle