Tikicchakasutta
“Tikicchakā, bhikkhave, virecanaṁ denti pittasamuṭṭhānānampi ābādhānaṁ paṭighātāya, semhasamuṭṭhānānampi ābādhānaṁ paṭighātāya, vātasamuṭṭhānānampi ābādhānaṁ paṭighātāya. Atthetaṁ, bhikkhave, virecanaṁ; ‘netaṁ natthī’ti vadāmi. Tañca kho etaṁ, bhikkhave, virecanaṁ sampajjatipi vipajjatipi.
Doctors
“Mendicants, doctors prescribe a purgative for eliminating illnesses stemming from disorders of bile, phlegm, and wind. There is such a purgative, I don’t deny it. But this kind of purgative sometimes works and sometimes fails.