Poggio Bracciolini, Facetiae (203):

On the doctor who used to give out cures by lot

“It is the custom in Rome that a sick person’s urine be sent to the doctor with one or two silver coins, so that he will consider the health of the patient. One doctor whom I knew would write various remedies on his note papers (which they call prescriptions) every night. He would then place them all in a bag. In the morning, when the urine was brought to him and he was asked for a remedy, he would place his hand in the bag and take out whichever leaflet happened to fall into his hand, and as he moved his hand through the bag he would tell the client (in the common tongue) Prega Dio te la mandi buona, that is, Pray to God that you get a good one. Wretched is the condition of those who receive their assistance from fortune, not reason.”

Facetum medici qui sorte medelas dabat