In digestion, a bolus (from Latinbolus, "ball") is a mass of food that (with animals that can chew) has been chewed at the point of swallowing. Under normal circumstances, the bolus then travels down the esophagus to the stomach for digestion. Bolus has the same colour as the food that has been chewed by the person and is different from chyme. The bolus is a rolled up ball-like structure formed when the animal is about to swallow. Its pH is alkaline because of the presence of saliva.