There is a "search" function that you could probably use, but I'll give you the benefit of the doubt.
Thank you letters for interviews?
I believe it is customary to send thank you letters to your interviewers (usually c/o admissions office, but call and see if there's a better place to send them) right after the interview.
Nothing too gushing or flashy, just that you really did appreciate their reviewing your file and chatting with you about medicine, a topic you can't get enough of, and that your experience was positive. i would recommend referencing something specific so they remember you and know it is sincere. (Of course if you follow this reply to the hilt it might not be sincere, I don't know.) Just make sure it shows you care.