You have to surf to cianwood city and go to the pharmacy then get the medicine from the guy behind the counter then go back to olivine city and give the medicine to amphorados.
Cianwood Pharmacy.
to get the secret potion(medicine)you need to go to cianwood
go to cianwood city then get it from a man
in cinawood city but you need surf
Surf to Cianwood City, there is a pharmacy there and the guy inside will give you secret medicine.
you go to the pharmacy in olivine
Secret Potion
first you have to guse surf to go to a city and there is a phamacy there
you save the anfaros by giving it the medicine incian wood city
you go to the city before the safarie zone.
building near Pokemon center on cinnabar island
You have to get to the top of the light house and she will ask you to get medicine in a nearby city, get the medicine give it to her and she will return to the gym. ☺