The digestive juice are the juices secreted by the glands present outside the digestive system and they help in digesting the food. When food is taken in the mouth, saliva is secreted by the glands called salivary glands into the mouth.
The saliva then mixes with the food that is chewed and it converts the food into soft moist ball called bolus which is easy to swallow. The saliva also digests the starch present in the food. Since saliva helps in digestion of food it, is called a digestive juice.