I have an infection that must be taken care of immediately. How can I find a doctor to see in Venice?
Ask your hotel for a recommendation.
Tonim,
Ask your hotel staff and they will know where to refer you.
I hope you get the help you need soon.
I agree with the others, check first with the desk staff at your hotel as they will probably know of an English-speaking Physician. A Pharmacy may also be able to provide information.
Good luck!
If you aren't in a hotel go to the nearest farmacia (Pharmacy) who will help. In an emergency call 112.
In researching this for myself I learned that there is a medical center (website looked like an urgent care in US) for tourists on st marks square. My issue cleared up before I needed to go, so I can't say either way if the center is good.
http://www.healthvenice.com/first-aid-san-marco.aspx