What is the largest organ in the digestive system?

The liver

The liver is, in fact, the second largest organ in the entire body (second only to your skin).

It has many functions in the :

Bile production – This is a fluid that helps to emulsify (break up into smaller droplets that can be more easily digested) lipids and fats in the duodenum. The bile, before being released, is temporarily stored in the gall bladder
Blood sugar regulation – The liver is very important for keeping blood sugar level constant. It converts excess glucose into glycogen for storage by the action of the hormone insulin. It releases the stored glycogen as glucose by the action of the glucagon hormone when glucose blood levels get low
Digestion and metabolism – It breaks down carbohydrate, protein and fats so they can be digested
Neutralising toxins – Such as alcohol and other drugs which are harmful for the body
Storage of nutrients – including vitamins and iron
Fighting infections – It helps to remove harmful bacteria from the blood that cause disease

The liver is a very big organ responsible for many important processes.