The main "drug" on MU's infamous "dry" campus would have to be alcohol. People party it up on campus, downtown, and in Greek houses and private homes. Pot does enter the realm of party-goers every once in a while, but big drugs, such as coke or meth, are not easily available. If someone is looking to get these drugs, there are ways, as there are ways everywhere else, but Mizzou students stick to celebrating with a good ol' beer instead of hitting the hard drugs. Most students have either tried or been around pot smoking, but it is not something that students set out to participate in.
Drinking on campus, mainly in the dorms, is not looked on favorably. Students will get in trouble and be written up. In many cases, for the first offense, they have to take a $50 class and are reprimanded by the RAs. During football games, parts of campus do become part of the "wet campus," but even in these areas, there are police patrolling for underage drinking (and they will give tickets—they don't give warnings). Drinking and driving is also strict. Both penalties for a DUI and an MIP (minor in possession) can be very severe, sometimes costing thousands of dollars. MUPD (the University of Missouri Police Department) as well as the CPD (Columbia Police Department) are starting to crack down on underage drinking and drunk driving.