Doctor
Doctors are one of the new features in Assassin's Creed II. Found on the streets of every city in black robes and mask with a beak-like shape, they can either refill Ezio's Health Bar for a fee, or sell him Medicine that can be carried and used later. They also sell him vials of poison for his Poison Blade.
Appearance and historical relation
The doctors in Assassins Creed II, as usual for their kind after one of the deadliest pandemics in human history (known as The Black Death ), dress in a long black cloak covered with a coating of wax, and a very primitive beak-shaped gas mask.
The Black Death plague peaked in Europe during the 14th century and is said to have killed over 30 percent of Europe's population.
Heal
Doctors can replenish all of your health by paying him a paltry sum of 50 florins. The price from the Doctor in Monteriggioni for his healing services, however, decreases as you renovate his stall.
Apothecary
Medicine
Doctors sell Medicine (75ƒ each) that acts as a healing item that can be carried with you anywhere you go. The number of Medicine vials you can carry at one time increases when you upgrade your Medicine Pouch from a Tailor. In game, the medicine itself is said to be smelling salts that act as painkillers.
Poison
Doctors sell Poison vials for a sum of 175 florins. When Ezio asks Leonardo why Doctors would sell Poison, he replies that, when given in high doses, "that which heals can kill". Poison is available only after upgrading Ezio's Hidden Blade with the Poison Blade. The Poison is useful for players who do not want to assassinate a target quickly or for those who rather create a distraction.