It's a common understanding that mixing drugs can have unknown side effects. This pertains to most everything from over-the-counter medicines to illicit drugs. The folks over at TripSit, which is a site dedicated to helping drug users stay safe, have made a comprehensive chart outlining how drugs interact with one another and if those interactions might turn dangerous. Let's have a look:
While many of the combinations might not be much of a surprise, it should be noted that according to the chart, cannabis doesn't have any interactions with other drugs labeled as dangerous. But of course, you should always use caution when combining drugs and no matter how much of an expert you are, it's probably a good idea to stick with one mind-altering substance at a time.