De Medicina is the oldest Western medical document after the Hippocratic writings. Written about 30 CE, it remains the greatest medical treatise from ancient Rome, and the first Western history of medicine. Celsus’s superb literary style won him the title of Cicero medicorum. De medicina deals with diseases treated by diet and regimen and with those amenable to drugs and surgery. The surgical chapters contain the first accounts of the use of ligature, excellent descriptions of lateral lithotomy and herniotomy, and the earliest discussion of the surgical remedies for mutilations -- what we now call plastic surgery, including plastic operations for restoration of the nose, lips, eyelids, ears, etc. Celsus also included numerous important contributions to dentistry, including some of the earliest Western accounts of the treatment of toothache, oral surgery, tooth extraction, and fractures of the jaw.
The text of De Medicina seems to have been neglected at some point during the Middle Ages, and when it was no longer copied, it was eventually lost. A copy was discovered in Milan in 1443. ISTC no. ic00364000. Digital facsimile from the Bayerische StaatsBibliothek at this link.