Where Does Chemical Digestion Occur?

Where Does Chemical Digestion Occur
••• Anetlanda/iStock/GettyImages

Chemical digestion occurs when acids, enzymes and other secretions break down the food we eat into nutrients. Chemical digestion starts in the mouth and continues in the stomach, but most of the process occurs in the small intestine.


Chemical digestion differs from mechanical digestion, which occurs in the mouth as the teeth grind and chew pieces of food. Some mechanical digestion also takes place in the stomach as the muscles churn food particles.

First Steps

Chemical digestion begins in the mouth. The enzyme amylase, found in saliva, starts breaking down carbohydrates.

Stomach's Role

Chemical digestion continues in the stomach. Hydrochloric acid and the enzyme pepsin work on digesting proteins.


A cocktail of enzymes in the small intestine completes the chemical digestion process. Most chemical digestion takes place in the duodenum portion of the small intestine.


Chemical digestion breaks down carbohydrates, proteins and fats into sugars, amino acids and fatty acids that the body can absorb and use as fuel.

Related Articles

Why Do We Need Enzymes for Digestion?
How Does pH Level Affect Enzyme Activity?
Five Major Organ Systems of the Body
What Are the 10 Major Body Systems?
What Is the Sun's Role in Photosynthesis?
How to Calculate Molarity From Molecular Weight
Where Does Respiration Occur?
How to Convert Pounds Per Square Foot to PSI
Does Oil Dissolve Rubber Gloves?
What Is Propylene Glycol
How to Make a 1% Sucrose Solution
What Is Sodium Lauryl Sulfate?
What Happens When Pepsin Mixes with Food in the Stomach?
How ADP Is Converted to ATP During Chemiosmosis within...
Sodium Bicarbonate Secretion in the Body
What Are the Chemical Names of the Four Macromolecules?
Industrial Uses of Pepsin
Names of the Enzymes in the Mouth & Esophagus
How Are Photosynthesis & Cellular Respiration Related?
Role of Enzymes in Chemical Reactions

Dont Go!

We Have More Great Sciencing Articles!