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Difference Between Egestion and Excretion

Last updated date: 26th Feb 2024
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Exploring the Characteristics of Egestion and Excretion

In order to understand the difference between Excretion and Egestion, one must be aware of the digestive process and the generation of waste. 

Meaning of Digestion

Digestion is the term used to describe the intricate process that allows the body's cells to absorb the nutrients from meals. All the nutrients that a person's body requires for health are present in food, but big, complicated molecules bind them. The body splits these substances into smaller components during digestion. They can then infiltrate cells and offer energy and other advantages as a result.

Waste Generation in Digestion

Undigested food components, fluid, and aging cells from the lining of the GI tract are examples of waste products from the digestive process. These products also include toxins, harmful substances that may have been ingested in the food, excess enzymes, bile juice, and other substances that need to be removed from the body. 

Need for Waste Removal

The waste products that accumulate from digestion and cell activity must be expelled by the human body. If these wastes are not eliminated, the cells may cease functioning, which might cause serious illness. This illness may possibly be lethal. The excretory system's organs assist in the body's waste elimination process.

This article aims to explain egestion and excretion in detail.

What is Egestion and Excretion?

Egestion: The egestion process in humans and other higher animal species involves waves of muscle contractions of the colonic walls that move the fecal waste toward the rectum. The rectum ampulla serves as a temporary storage space for feces. Rectal walls enlarge when fecal matter builds up. As a result, the internal anal sphincter relaxes and the external anal sphincter skeletal muscle contracts, stimulating the stretch receptors in the rectal walls. There is a desire to release the waste as a result.

Body Parts Involved in Egestion

As the undigested food is moved down the large intestine and then removed from the body, the following body parts play a crucial role in completing the egestion process-

  • Rectum

  • Internal and External sphincters.

  • Anus

Excretion: Excretion is the method used by organisms to remove or expel the waste products generated from their metabolisms. Cells must undergo specific metabolic processes in order to exist. As these processes occur, certain byproducts are created, some of which can be poisonous or fatal to the cells if they are allowed to build up. These wastes are collected during excretion and removed from the cell. These wastes then need to be eliminated from the body in multicellular creatures.

Body Parts Involved in Excretion

Since metabolism occurs in almost every cell in the body, metabolic wastes are accumulated throughout the cells and can be removed from various exit points. Some of the body parts that help eliminate these metabolic washes include-

  • Kidneys

  • Lungs

  • Skin.

Egestion and Excretion Difference







Egestion involves the removal of undigested food materials. 

Excretion involves the removal of metabolic wastes. 


Body parts

Occurs mainly through the anus but sometimes through the mouth. 

Can occur through the skin, kidneys, and even the nose.  



The output usually involves leftover food called feces. 

The output may involve carbon dioxide, urine, and even sweat. 



This process is observed only in animals. 

This process is observed in both plants and animals. 



Feces are formed in the rectum. 

These metabolic wastes are generated in the cells of the kidneys, skin, etc. 



The toxicity of feces is less when compared to metabolic wastes. 

Metabolic wastes like urine contain highly toxic urea. 


Excretion is the term for your body getting rid of metabolic waste and egestion describes your body's elimination of unprocessed waste. When you consume food, waste substances that are often eliminated from the body are produced, including mucus, uric acid, porphyrins, cholesterol, etc. These waste products are eliminated from your body through a variety of mechanisms. It makes use of the kidneys, which eliminate the wastes like uric acid.

FAQs on Difference Between Egestion and Excretion

1. What is the significance of Egestion?

It is essential to the health and survival of both unicellular and multicellular organisms that waste is disposed of properly. Animals must consume (ingest) chemical substances that contain energy, extract some of the energy to fuel their biological functions and discard any waste products or byproducts that result from the energy extraction. Egestion is a crucial function in both humans and animals because it allows the body to get rid of undigested food.

2. What is the significance of Excretion?

Excretion is the process through which the body expels wastes and extra water. The stability of the organism's internal environment, or homeostasis, depends on it. Excretion also aids in maintaining acid-base balance, inorganic ion and water balance, and osmotic pressure. All living things require excretion, although warm-blooded, active animals with high metabolic rates require it more than others. Allowing metabolic wastes like urea to build up in the body will create toxicity and eventually harm the body's cells.

3. Explain the difference between Excretion and Egestion.

When the body is unable to break down certain ingested food materials, they are clumped together with the help of mucus and directly removed from the body through the anus. This process of removing undigested food material is called egestion. However, when the digested food is broken down to release energy, certain metabolic wastes are generated, The removal of these wastes like urea and carbon dioxide is called excretion. Thus, egestion removes non-metabolic waste while excretion removes metabolic waste.