I participated in the selection procedure for Medicine in Groningen last year. Can I participate again?

No, candidates can only participate in the selection procedure for the degree programme in Medicine in Groningen once. 
When you are registered in Studielink for the degree programme in Medicine in Groningen after 15 January, this counts as participation even if you later decide not to participate.

An exception can be made for those candidates that fail their final high school exams in the year they participate in the selection procedure (regardless of their performance in the selection). In this case you have to contact the University of Groningen via the form Selection and placement. If you are on time, you may participate again.