talk to jasmine in the lighthouse at olivine city and then go to cianwood and talk to the pharmasist
Chat with our AI personalities
if you mean the medicine for 'amphy' in the light house, go to the medicine man in cianwood city he will give you a 'secret potion'
you go down to the house next to the Pokemon center and inside is this guy, talk to him and he will give a secret potion.
Cynthia will give it to you.
You get the secret potion by talking to the pharmacist in Cianwood City. His house is in the south, south east of the gym.
cianwood city