The Compendium of Caraka 1.11.34

1.11.34

atha khalu traya upastambhāḥ, trividhaṃ balaṃ, trīṇyāyatanāni, trayo rogāḥ, trayo rogamārgāḥ, trividhā bhiṣajaḥ, trividhamauṣadhamiti //

Now indeed, there are three sub-pillars, threefold strength, three etiologies, three diseases, three pathways of disease, three types of physicians, and three types of medicine.