Saliva contains the enzyme salivary amylase (ptyalin), which breaks down complex carbohydrates such as starch into smaller fragments like maltose. It also contains lysozyme that controls oral bacteria, and mucus that lubricates the oral cavity.

Saliva does not act on disaccharides. Digestion of disaccharides (such as maltose and sucrose) takes place in the small intestine through intestinal brush border enzymes.