Digestive enzymes are proteins produced by the stomach, small intestine, and most importantly pancreas. Digestive enzymes are necessary for the breakdown of carbohydrates, proteins, and fats. The moment we smell food, our bodies start to produce saliva and digestive enzymes, preparing to receive food. There are 3 main digestive enzymes: amylase for breaking down carbohydrates, lipase for breaking down fats protease for breaking down protein. There is also sucrase for breaking down sucrose and lactase for breaking down lactase. The latter two are often ones certain people don't produce enough of, resulting in intolerance, bloating, gas, diarrhea or constipation, etc.