Clyssus is a big word that means "washing out the insides using water". It's like when you take a bath or shower to clean your body, but sometimes we need to clean the insides of our bodies too! When we eat and drink, sometimes things get stuck or make us feel bad. Clyssus helps us clean out our insides so we can feel better. It's like using a special hose with water to clean the inside of your tummy. It might not be fun, but it can make you feel a lot better!