Phosphatidyl cholines are a class of phospholipids that incorporate choline as a headgroup. They are a major component of biological membranes and can be easily obtained from a variety of readily available sources, such as egg yolk or soybeans, from which they are mechanically or chemically extracted using hexane. They are also a member of the lecithin group of yellow-brownish fatty substances occurring in animal and plant tissues.

Dipalmitoyl phosphatidylcholine (a.k.a. lecithin) is a major component of pulmonary surfactant and is often used in the L/S ratio to calculate fetal lung maturity. While phosphatidylcholines are found in all plant and animal cells, they are absent in the membranes of most bacteria,[1] including Escherichia coli.[2] Purified phosphatidylcholine is produced commercially.

1. Phophatidic is a kind of necessary substance to transfer fat from liver, whick can increase albumens transfering ability, lighten fattiness aggradation so as to prevent and cure fat liver and increase the function of detoxifcation. 
2. Its emulsification is help to the digesting, absorbing, transfering of fattiness, which also can restore the liver cell to advance the regeneration of liver cell. 
3. Increase the animals vigor of immunity system so as to buildup immunity. 
4. Phophatidic can resume the situation of decrease of laying rapidly. 

It is mainly used in food industries such as ice cream, candy, soya milk, sausage and ham, chocolates and soft drinks; it is also used in tanning industry for high grade leather.