Cianwood Pharmacy.
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'
Surf to Cianwood City, there is a pharmacy there and the guy inside will give you secret medicine.
building near Pokemon center on cinnabar island
After returning to the sick Pokemon in the light tower (bring your medicine from Cianwood with you).
secret potion which you get by surfing to cianwood starting from the beach in olivine
Just evolve a mareep
You must Surf to Cianwood from Olivine and get the medicine in one of the buildings. Then you must either Surf back to the Lighthouse or beat the Gym Leader, Chuck, and get HM Fly from the lady standing outside the Gym and Fly back to Olivine.
I Would Suggest Training At Whirl Islands And Around That Area. You Can Also Go To The Lighthouse And Give Amphy The Medicine And Challenge Jasmine And Pryce. They Aren't That Tough.
Cianwood Pharmacy.
Go west of blackthorn city and in your party have the following Pokemon - Gyarados , Nidoking , dragonite and todile and capture it with a heavy ball
You first have to talk to the gym leader that is on top of the light house in Olivine City, she will ask you to go and get medicine for the Ampharos(Amphy) that powers the lighthouse. Then you go and talk to the guy in the Cianwood to get the SecretPotion.
to get the secret potion(medicine)you need to go to cianwood
When amphy the ampharos is sick, she'll be at the top of the lighthouse in Olivine City. Surf to Cianwood City and get the Secretpotion from the pharmacy. Then beat the gym there and you'll obtain Hm fly, Fly back to olivine and go to the top of the lighthouse to give the potion to amphy.
You must go to the Cianwood City Pharmacy.. :)
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'
go to cianwood city then get it from a man