The Medieval Hazmat Suit.

The bubonic plague, or the Black Death, was the third deadliest pandemic in human history. Even though Fourteenth century physicians could not figure out what was causing such a plague, they quickly figured out that it was highly contagious.
To protect themselves from the “bad air,” these plague doctors wore their own version of a Hazmat suit. This suit included a large beaked head piece that was filled with vinegar, sweet oils and other strong smelling compounds to counteract the stench of the dead and dying plague victims.
The physicians also wore a large brimmed hat, long black overcoat, and leather breeches. The overcoats were usually coated in wax as an extra precaution.
Unfortunately, these roaming plague doctors probably did more harm than good. They traveled from town to town administering to the sick. It is unknown if their remedies did any good, but it is a certainty that many of these doctors helped to spread the plague across Europe.