there can be harmful effects but they dont usually happen...

the main thing is that the drug amplifies the effect of the weed while the weed amplifies the effect of the drug. so basically you just get really fucked up...

mixing two is alright, but three and four is pushing it. for instance, take a vicodin, drink a beer or two, smoke a bowl and you will be very fucked up, and its pretty good as long as you only take one vico, and only drink 3 beers at most(unless u have really high tolerance).