¡Doctor!

DOCTOR! is a manga by Ippongi Bang staring the mysterious young Doctor (Yeah, that's his name) in a fantasy world taking place in Latin America.The art of surgery has been lost, and illnesses are caused by demons and forces of Darkness. Doctor travels with this little blob named Liquido Medio and they travel around from place to place curing and helping people along the way.

(Source: MangaUpdates)