Excretion is the process where an organism excretes the byproduct of a metabolic process using the different cellular and organ functions. Egestion, on the other hand, is the term associated with the excretion or elimination of undigested food from the digestive system of an animal.
Basically egestion is when undigested food becomes waste and comes of out the body through the anus, and excretion is when your body removes toxic and waste material and excess products from organisms.
