The absorption takes place in the following way in different parts of the digestive system - 

i. In mouth : Certain drugs are absorbed into the blood capillaries lining the mucosa of the mouth and the lower side of the tongue. 

ii. In stomach : Absorption of water, simple sugars and alcohol takes place in the stomach.

iii. In Small Intestine : It is the principal organ for the absorption of pnutrients. The digestion is completed here and the final products of digestion such as glucose, fructose, fatty acids, glycerol and amino acids are absorbed through the mucosa into the blood stream and lymph.
 
iv. In Large intestine : Absorption of water, some minerals and drugs takes place in the large intestine. .