It's always been said that there are no Game Genie or Action Replay codes for this game. The reason being that when the game is used with such a cheat cartridge, the saved files would often become corrupted or even deleted altogether. With the rise of Emulators, however, it seems that some codes have emerged, and although I am unable to test them, here they are (do let me know if they don't work!)...

Hit your opponent to gain a level

Ignore the 58 exp, it is actually 99 exp.
HERO: NSYS-99BT
CHESTER: NSYS-99FA
JAHA: NSYS-99G2
KAZIN: NSY9-99AT
KIWI: NSY9-99EA
PETER: NSY9-99F2
MAY: NSY9:99HT

supplied by: Don Schwinghammer

More Experience, More Gold

99 experience for Hero: FFE8300063
99 experience for Tyrin: FFEBE80063
Extra experience For Chester: FFE8A00063
Extra experience For Jaha: FFE8D80063
Extra experience For Kazin: FFE9100063
Extra experience For Kiwi: FFE9800063
Extra experience For Peter: FFE9B80063
Extra experience For May: FFE9F00063
Extra experience For Sarah: FFF8680063
Alternate code: FFFE868006
Extra experience For Slade: FFF9480063
Extra gold: FFF6037FFF

Gain a level when Medical Herb is used

EV1A-CAPR

supplied by: Silverbullet4261@aol.com