I agree with AdinaP. Applying toothpaste over pimples really works to reduce pimples and is one of the best ways to dry up a pimple fast and get clear skin overnight.
I heard about using toothpaste years ago and do use it myself. I don't know technical terms but by putting a blob on the spot overnight it dries up the area and stops the spot producing a head or getting too inflamed. It will cause a dry area where it is applied if used a lot over a few days but this soon goes by exfoliating the skin and using a good moisturiser. I would recommend it as a quick fix but I am sure it would do more harm than good to use it too often and on large areas.