you have to give your pokemon the specific medicine you want to give the gym leader and the battle him
In Cianwood City you receive the medicine from the medicine shop. To give the medicine to the gym leader you have to go to the top of the lighthouse in olivine, which is where she will be. She will then return to her gym where she will battle you. Be careful - her Pokemon (2 magnemites and a Steelix) can be tough! Good luck! :)
you go across the sea and end up in clainwood city then go to the farmacy the second building to the left then talk to the man and he will give you some medicine then beat the gym leader on clainwood city then go out and his a woman will give you the hm fly then fly back to olivine and give the gym leader the medicine and then you can go to her gym and battle her.
Fly to cinnawood and then go to the medicine shop and the guy will give the pokemon medicine
You must give the Secret Medicine, which can be obtained at Cianwood City.
Go to Cianwood Town and go into the house that has a sign by it that says "Medicine" in it. Ask the guy for medicine. He says he is busy but then you tell him its for the Olivine gym leader's Ampharos. He will accept and give you the medicine. Climb back up the tower and give the medicine to the gym leader. Hope it helped. :)
Jasmine(the gym leader) wants a secret potion for Ampharos, the lighthouse pokemon. To get the potion, you have to go to Cianwood City. There you can beat the 5th gym leader and then go to the pharmacy and get the medicine. Fly back to Olivine City and give it to her.
Go back to Olivine City and give the medicine to Jasmine. Then fight her at the gym.
I think you'll need to give Amphy the medicine in the Lighthouse and battle Jasmine, then you can battle Chuck, which the is 5th Gym Leader in Cianwood City.
It's a specific key item, not an actual item.
The medicine is in Cyanwood city.
The girl in the tower, I'm assuming, is Jasmine in the Olivine lighthouse. You have to surf west to Cianwood. There is a pharmacy there that will give you the "Secret Medicine". While you're there you can beat the 6th gym leader, then return to Olivine and give the medicine to Jasmine, after which she will return to her Gym.
you can find it in the ciann city pharmacy