What is folic acid? Folic acid is a B complex vitamin, also called vitamin B9 or folate. It is one of the essential nutrients for the human body and is mostly found in fresh vegetables, beans, liver and other foods. The physiological role of folic acid in the human body is very complex. It not only plays an important role in the health of mothers and babies during pregnancy, but can also help prevent a variety of chronic diseases and maintain the normal functioning of the body. The functions and functions of folic acid The main functions of folic acid in the human body are as follows: