Vitamins are normally categorized as water-soluble and fat-soluble. Those that are water-soluble are flushed out on a regular basis and not stored in the body in any appreciable amount. As such, they need to be replenished on a daily basis and risk of toxicity is lower than with fat-soluble vitamins. Fat-soluble vitamins are stored in our fat cells and can accumulate over time. As such, generally smaller amounts are needed and the risk of toxicity from large doses is greater.