You go to Cianwood city south of Olivine City and talk to the guy in the pharmacy. He will give you the secretpotion which you then give to Jasmine (the girl with the sick pokemon) and she gives it to the pokemon. After that you can battle Jasmine as she is the sixth gym leader and she uses steel types.
pass the missions
go across the water from the light house
South-west of the light house.
Use the elevator at the 1st floor.
You can't take it you have to catch a mareep evolve it into a flaffy then evolve it again
secret potion. you can find it at the olivine city in that medicine shop.
The Light house is at Olivine city. First use HM Fly and fly to "Olivine City". When you get there walk down to the bottom right corner of Olivine city and there's the light house.
Go to that little island thing were you get Shuckle from and get some medicine from a house there and give it to her so she can heal her Ampharos.
Pokemon ranger tracks of light
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 can get it by getting a pichichu in pearl trade it to heartgold
u have Kurt make it (in azalea)