Difference Between Egestion and Excretion (With Table)

The removal of waste products from the body is a necessary process for an organism. The removal of waste products takes place in an organism through different means in every organism.

Egestion and Excretion both are the waste removal process. The pathways are different along with the organs or cells that are involved in the process.

Egestion vs Excretion

The difference between Egestion and Excretion is the organs that are involved in the process. Egestion is the process in which an organism expels out waste, whereas Excretion is a metabolic process occurring in the multicellular organism.

The Egestion is a simple process of discharge of waste materials. In plants, transpiration through stomata, contractile vacuole in a unicellular organism like Amoeba are examples of Egestion.

Excretion is the metabolic process occurring in a complex organism. These organisms usually have organs to expel out the waste. The organs like the kidney, liver are the organs that are involved in the process.

Comparison Table Between Egestion and Excretion

Parameters of ComparisonEgestionExcretion
DefinitionThe discharge of undigested food from the organism is called Egestion.The removal of metabolic waste from the body is known as Excretion. 
OrganismsUnicellular and Multicellular both show Egestion.The multicellular animals possess excretion.
OrgansThe vacuoles and intestinal cells in animals are mainly involved in egestion.The kidney and liver are involved in the production of the metabolic waste and the rectum and anus are used to expel it out from the body.
Cell’s InvolvementThe vacuoles consist of lysozymes that are mainly involved in the egestion.The waste pass through the cell of the intestines where absorption of nutrients takes place.
ExampleThe removal of waste in Amoeba takes place with the contractile vacuole’s help. It absorbs the useful product from the food, and the undigested food is expelled out of the amoeba. The urea excretion in humans is the best example of Excretion.

What is Egestion?

The egestion is the process of expelling out waste. The undigested food is usually expelled out from the organisms. The unicellular organisms like Amoeba and paramecium are the organisms that best suits the example of the Egestion.

The Amoeba engulfs the food with the help of Pseudopodia. The food particles form a food vacuole. After that, when the food is digested, the undigested food is left, and the lysozymes, along with undigested food, produce a contractile vacuole. The vacuole is expelled out from the amoeba, and this is known as egestion.

The egestion is related to digestion in humans and other complex organisms. The ingestion is the intake of food, and egestion is the process of expelling undigested food. The egestion involves the intestine, where the absorption of food takes place.

In humans, Egestion helps in absorbing the nutrients that are necessary for the body. The process helps in completing the nutrient requirement of the organisms.

In plants, a simple exchange of gases through stomata and loss of water via transpiration are included in the Egestion. The transpiration is based on the concentration gradient.

What is Excretion?

The process by which an organism excrete out metabolic waste is called excretion. It is a life process that is very important to survive. The Excretion can take place through the nose, anus, and skin. The secretion of sweat and oil from the skin, release of carbon-di-oxide from the nose, urea, and uric from the anus are included under the excretion.

The excretion mainly occurs in the kidney, where urine is formed. The excretion also helps in maintaining the osmotic pressure in the body. The water content of the body is also maintained by excretion. The kidney has a key role in the process. The kidney filters out the waste from the blood and reabsorbs the ions needed, and the rest is excreted out.

The metabolic waste differs in every organism. Aquatic animals excrete ammonia, terrestrial animals like humans excrete urea and urine, and save (the animal kingdom containing mammals who can fly, for example, birds) excrete uric acid. The differences in the metabolic waste of the organisms are because of the presence of water.

Excretion is a process that requires energy. It is therefore also considered under the catabolic process. The energy that is utilized during Excretion is in the form of ATP. The ions concentration across the cell membrane is also maintained with the help of Excretion.

Main Differences Between Egestion and Excretion

  1. The removal of undigested food is called Egestion, whereas Excretion is the removal of metabolic waste.
  2. The Egestion is a part of digestion in animals but, Excretion is a life process in animals.
  3. The egestion takes place in both unicellular and multicellular organisms. But, excretion is a complex process and takes place in a multicellular organism.
  4. The egestion expels out the waste through the mouth, anus, and vacuole. Whereas the Excretion expels out the waste through the anus, nose, and skin.
  5. The egestion is just a simple process to remove undigested food, but Excretion is a complex process that removes toxic waste from the body.
  6. The egestion plays an important role in completing the nutrients of the body, whereas excretion helps in maintaining osmotic pressure in the body.


Egestion and Excretion both are processes that are involved in expelling out waste in the body. But, both process differs. If we talk about these processes in context to the humans. A slight difference can be seen in both of them. Hence sometimes, we use both words to describe the same process.

The Egestion is a part of digestion but, excretion is a life process that is necessary to survive. It plays a very important in maintaining the osmotic concentration in the body. The osmotic concentration maintains the ionic balance in the body.


  1. https://link.springer.com/article/10.1007/BF00361238
  2. https://www.taylorfrancis.com/chapters/edit/10.1201/9781003078920-22/excretion-michel-jangoux
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