What is poo?

  • Poo (faeces) is the waste that remains after food has been digested and its nutrients absorbed by the body.

  • Poo contains water, fibre, bile and bacteria.

  • Many types of bacteria live in your digestive system. Some of these help to keep you healthy.

Find out everything you wanted to know about poo

The digestive system breaks down food into smaller molecules. These smaller molecules pass into the blood, which carries the nutrients in these molecules to where they are needed.

Poo is the waste that remains after food has been digested and its nutrients absorbed. The scientific word for poo is faeces. Poo contains water, fibre, bile and bacteria.

Fibre

Fibre comes from plants, and is not broken down in the digestive system. It adds bulk to food, and helps it to move through the digestive system.

Bile

Bile is made in the liver. It is a yellowish-green alkaline liquid. It breaks big lumps of fat into smaller lumps, and big drops of oil into small droplets.

Bacteria

Up to a thousand different types of bacteria live in your large intestine. Some bacteria species live in everyone, other types live in some people but not others. This makes you unique, no-one else has exactly the same gut bacteria as you.

There are many types of bacteria that help keep you healthy:

  • Gut bacteria feed on fibre. This produces waste products that nourish the large intestine lining.

  • Some types of bacteria make vitamins.

  • Some bacteria help your immune system to work properly, so preventing disease.

Not all gut bacteria are helpful. Some types may cause infection, and others may increase the risk of cancer.

What does your poo say about you?

Specialist doctors use the shape, colour, smell and texture of poo to help diagnose disease:

  • Normal poo is like a soft, smooth sausage, or it might be sausage-shaped with cracks in the surface.

  • Separate, hard lumps show that you are not drinking enough water.

  • Mushy or liquid poo shows that you have diarrhoea, perhaps caused by an infection.

Poo quiz

Test your knowledge with this quick quiz.

How to model digestion using tights
What is digestion?
What are vitamins and minerals?

Nutrition, digestion and excretion, there's more to learn...