One legitimate way of expanding your medical writing portfolio is by submitting articles to online health magazines or related Web sites. I just came across one such publication that accepts articles from freelance medical writers:
America's Medical Magazine
This is a web-based medical magazine dedicated to bringing the most compelling stories about the human side of any kind of medical condition to its readers. Accepted stories cover surgery, psychiatry, medicine etc from a provider, family, caregiver or individual perspective. You do not have to be an established writer to contribute to this magazine. Articles are non-fiction stories. Information articles are not solicited.
One time rights or reprints for electronic rights are bought as agreed with writers. Having your work accepted has more to do with the needs of the magazine than how good your write up is. The initial step is for you to send an email query with enough enough information about your proposed story. All initial communication is via email. You can send email to firstname.lastname@example.org
Your email should describe the nature of your story, how long it will take to complete and any other detail you feel is important. The magazine pays 5 cent per word. Payment is made on acceptance. Listing source here.