The sign, which named the dentist, was placed on the clinic’s door on Wednesday morning, sparking “indignation” in the town of Massa, Il Secolo XIX reported.
A photograph of the notice was taken by a patient and published on the newspaper’s website.
It read: “We bring to your attention that a homosexual dentist works here…please take precautions to protect your health.”
The notice was signed by a supposed “entity for the protection of patients against diseases contracted in dentistry”.
Alessandro Bandoni, the president of the equal opportunities commission for the neighbouring town of Carrara, was quoted by the newspaper as saying: “We will find who is responsible for this worthless and unequalled act, and take legal action.”