After having faced Natsume/Sabrina, Kyou/Koga might seem like a piece of cake. His Poison-type Pokemon can easily be beaten with Ground and Psychic-type Pokemon, so the TM that Natsume/Sabrina gave you should help a lot. Dig is also a big help, since there's more chance that the Poison attacks won't hit you. Obviously, bring a lot of Antidotes and/or Full Heals. Watch out for Matadogas/Weezing's Toxic attack! It drains more and more HP out of your Pokemon as the battle progresses.

Suggested Pokemon levels: 35+

Items Received: TM06, Toxic