Aulus Cornelius Celsus (c. 25 BC – c. 50 AD) was a Roman encyclopaedist, known for his extant medical work, De Medicina, which is believed to be the only surviving section of a much larger encyclopedia.

[2] Some incidental expressions in his De Medicina suggest that he lived under the reigns of Augustus and Tiberius; which is confirmed by his reference to the Greek physician Themison as being recently in his old age.

He has been identified as the possible dedicator of a gravestone in Rome, but it has also been supposed that he lived in Narbonese Gaul, because he refers to a species of vine (marcum) which, according to Pliny,[4] was native to that region.

[5] It is doubtful whether he practised medicine himself, and although Celsus seems to describe and recommend his own medical observations sanctioned by experience, Quintilian says that his volumes included all sorts of literary matters, and even agriculture and military tactics.

[9] In the treatment of disease, Celsus's principal method was to observe and watch over the operations of Nature, and to regulate rather than oppose them, conceiving that fever consisted essentially in an effort of the body to throw off some morbid cause, and that, if not unduly interfered with, the process would terminate in a state of health.

In addition, he describes many 1st century Roman surgical procedures which included removal of a cataract, treatment for bladder stones, and the setting of fractures.