Rare Candy is a kind of medicine introduced in Generation I.
When used from the Bag on a Pokémon, it increases that Pokémon's level by one, up to level 100. After leveling up, it will have the minimum required experience for its current level.
•Hidden at Viridian Forest, Route 17, Route 27, Route 108, Route 127, Route 132,Cerulean Cave, Mt. Silver 2F, Bell Tower Top, Olivine City, Violet City, Oldale Town, Valley Of Steel Entrance,Vulcan Path, Vulcan Forest
•Possible boss reward by Boss, Brock, Shamac, Shary & Shaui, Lance, Misty, Neroli, Terminator, Birch, Thor, Gingery Jones, Raikou Guardian, Suhuzen, Letrix,Maribella, Professor Rowan, Zetsu and Shieon
•Possible Game Corner reward
•Possible PokéStop reward
•Solaceon Daily Quest - Once every 4th day streak