The Romans drank all sorts of disgusting concoctions for their health. Gladiator’s blood does seem a little extreme, however:
Epileptic patients are in the habit of drinking the blood even of gladiators, draughts filled with life as it were; a thing that, when we see it done by the wild beasts in the same arena, inspires us with horror at the spectacle! And yet these persons consider it a most effective cure for their disease, to drink he warm, breathing, blood from man himself, and, as they apply their mouth to the wound, to draw forth his very life; and this, though it is regarded as an act of impiety to apply the human lips to the wound even of a wild beast!
Pliny the Elder, Encylopedia28.2