The passage of small food molecules through the wall of the alimentary canal and into vessels that can transport them within the body is call Absorption Process. Basic objective of this lecture is to present on Absorption Process. Here also briefly focus on alimentary canal. The alimentary canal (or gut) is a long tube inside the body. Any food in the alimentary canal is still outside the cells of the body. To get inside the molecules of the food have to be able to pass through the wall of the alimentary canal.