where would I file a complaint regarding a doctor's unethical practice
in massachusetts?

toll free numbers??

dux-ga,

The Massachusetts Board of Registration in Medicine can take your
complaint.  Their procedures, forms, and Q&A's can all be found at
their site:


http://www.massmedboard.org/consumer/complaint.shtm


I trust this is the information you were looking for, but before
rating this answer, please let me know if there's anything else you
need.  Just post a Request for Clarification, and I'll be happy to
assist you further.

All the best,

pafalafa-ga


search strategy --  Google search on [MA department health] and
followed links from there to the Board of Registration site.