I'd have to look at the student handbook again for the specifics, but basically a D in first year classes is equivalent to an F. That being said though, they really do try to ease you in, and there is a lot of support from the school, peer mentors, and individual professors offered to anyone who should fall into the danger zone. For example, a lot of people were in danger of failing (D-ing) histology last semester, but the prof offered several opportunities for make-up points and I heard he also held special review sessions focused on aiding those who were struggling. So I would not say it is "easy to fail out", there were just some very difficult professors in certain classes prior to this year (well...there still are some difficult profs, but they really don't want so many people to fail again, and will work with the class on whatever concepts may be causing issues!)