Potions/Effects can be added to your player to give you a good effect. Some potions can give off a bad effect. The potion effect Nausea will make your screen swirl and go crazy. That is a bad effect. A good effect is Health Boost which will add more hearts to your character. The higher level of Health Boost, the more hearts you will get. Some good effects can make you breath under water for longer, not lose as much hunger, and make you stronger. Examples of bad effects can poison you, make you slower, and give you bad luck.