Fourteenth century physicians didn't know what caused the plague, but they knew it was contagious. As a result they wore an early kind of bioprotective suit which included a large beaked head piece. The beak of the head piece, which made them look like large birds, was filled with vinegar, sweet oils and other strong smelling compounds to counteract the stench of the dead and dying plague victims.

This statement describes the authentic plague doctor costume worn by physicians during European plague epidemics, particularly in the 17th century. The beak-like mask was indeed filled with aromatic substances like vinegar, herbs, and oils to ward off miasma (bad air) thought to cause disease. However, the statement's framing as a known-contagion fact with modern bioprotection understanding makes it false - 14th-century physicians operated within the miasma theory and didn't know about contagion in the modern germ theory sense.