The Compendium of Caraka 8.11.16

8.11.16

sarvakarmaguṇakṛdguruṇokto bastirūrdhvamatha naiti nābhitaḥ/
nābhyadho gudamataḥ sa śarīrāt sarvataḥ kathamapohati doṣān&//

“The enema has been declared by the preceptor to produce the benefits of all procedures, yet it does not go upward beyond the umbilicus; / the rectum is below the umbilicus; therefore, how does it remove the doṣas from the entire body?”