In moderation they are good. If you eat a typical western diet it is recommended to take a multi vit that is contains 100% of your recommended dail
alowance. However too much can be counter productive or even fatal. For instance too much vit E can thin the blood and even promote hemoraging if you
are a regular user of anti coagulants like warfarin or aspirin.
Your body needs vitamins. Varies depending on factors such as age, sex and how physically active you are. Are they bad? Your body needs vitamins.
However, it has to be done in moderation. Taking too much of anything can spell trouble. Do you need to take a multi-vitamin? Of course not you can
get everything you need from the local grocery store, but most americans do not get their recommended daily amount from the foods they typically
eat...which is why they take a multi-vitamin pill. Marketing ploy? maybe some of that =)