The Compendium of Caraka 3.5.8_12

3.5.8_12

purīṣavahānāṃ srotasāṃ pakvāśayo mūlaṃ *sthūlagudaṃ ca, praduṣṭānāṃ tu khalveṣāmidaṃ viśeṣavijñānaṃ bhavati; tadyathā---kṛcchreṇālpālpaṃ saśabdaśūlamatidravamatigrathitamatibahu copaviśantaṃ dṛṣṭvā purīṣavahānyasya srotāṃsi praduṣṭānīti vidyāt/

The large intestine and the rectum are the root of the channels carrying feces, and when these are vitiated, this is their specific diagnostic knowledge; namely: seeing one evacuating with difficulty, in minute amounts, with noise and pain, excessively liquid, excessively scybalous, and in excessive quantity, one should know that his channels carrying feces are vitiated.