Phagocytosis is a process used by cellular organisms to engulf food. Once the organisms like Amoeba identify food they use phagocytosis to extract its nutrients and convert it into energy. The process operates in three principal steps: 1) Encapsulation of food by cell membrane, 2) Assimilation of food and 3) Expulsion of waste.

The mechanism of this process can be used to isolate bad cells in animals thereby enabling us to target drugs to specific cells.