You're wrong on some count here. You never want to buy vitamins on prescription -- believe it or not, doctors prescribe vitamins that are usually in the wrong form for best absorption. They know almost nothing at all about supplements and so don't know the best ones to buy, and pharmaceutical companies usually use the cheapest ingredients they can find. Next, never buy a vitamin or any supplement in a drug store. They also always sell low quality supplements. The best ones are found in the best health food store in your area, and I don't mean a GNC. Next, vitamins are not considered "food." Food is food, vitamins are a supplement. Some vitamins do contain food, such as spiraling, an algae, or food sources of nutrients, but you can't fit food into a pill, obviously. They don't replace food. Next, vitamins always contain more than you need because, not being food, your body is going to evacuate a lot of it before you digest it and get it into your system. Next, you only take a specific vitamin, like a B vitamin, if you have something going on that requires that. Otherwise, you take a good multivitamin as insurance because in our society, all the food we eat, although we have access to tremendous variety no previous generation had, is fairly old by the time we eat it and if you don't buy organic food, you might be getting food grown in dead soil. So taking a multi is not a bad idea. Many people need to supplement Vitamin D because we have been told to stay out of the sun, the natural way to get it. So supplements can be a good idea, but you have to buy good quality ones. Lastly, whenever you take a new supplement and you feel like it's making you ill, stop taking it. You should actually do the same with medication, though with that you usually have to talk with your doc first because stopping some drugs can be harmful if not done correctly. But with a supplement, just top taking it. If the problem goes away, it was the supplement, and stop taking that one. One thing that can cause this is using ingredients that don't absorb well or a reaction to the many fillers and binders and artificial colors etc. drug store vitamins usually put in their supplements.