Ash has a tummy ache while he, Misty and Brock were trying to get to Ecruteak City caused by eating twice his body weight in food. They soon meet an elderly man by the name of Old Man Shuckle. After having some Pokémon medicine Ash felt 100% better. As a Breeder and medicine man himself, Brock was fascinated to meet a fellow medicine master. Apparently he is looking for a shiny Shuckle. Can Ash and co. be able to find it, and why do the surrounding Pokémon look like they're in a daze?
This episode's English title is a reference to the phrase "a bitter pill to swallow".