Berachot 60b

On entering a privy one should say: ‘Be honored, ye honored and holy ones that minister to the Most High. Give honor to the G-d of Israel. Wait for me till I enter and do my needs, and return to you’. Abaye said: A man should not speak thus, lest they should leave him and go. What he should say is: ‘Preserve me, preserve me, help me, help me, support me, support me, till I have entered and come forth, for this is the way of human beings’.

When he comes out he says: ‘Blessed is He who has formed man in wisdom and created in him many orifices and many cavities. It is fully known before the throne of Thy glory that if one of them should be [improperly] opened or one of them closed it would be impossible for a man to stand before Thee’. How does the blessing conclude? Rab said: ‘[Blessed art You] that heals the sick’. Said Samuel: Abba has turned the whole world into invalids! No; what he says is, ‘That heals all flesh’. R. Shesheth said: ‘Who does wonderfully’. R. Papa said: Therefore let us say both, ‘Who heals all flesh and doest wonderfully’.