According to Ayurveda, Vata, Pitta and Kapha are produced in human body, therefore they are called Dhatus. Appropriate amount of Dhatus in our body indicates good health. While imbalance in them indicates diseases. Defects in these three Dhatus causes diseases. In Ayurveda, eighty types of diseases are described caused due to defects in Dhatus. Pitta helps to digest food, but less amount of pitas causes diseases like constipation, acidity and dysentry. Similarly, defect in Kapha also causes diseases.
Thus, all these Dhatus should be in appropriate quantity in the body. Then only fitness can be maintained. But defect in them causes various diseases.