In my Explorers of Sky game, my Raticate was confused. It threw a Silver Spike at Ledian. This is the message it said:
Raticate threw the Silver Spike! Guts boosted its power!
Does Guts actually boost throwing item power?
>A Pokémon with this Ability will gain a 100% bonus to physical attack, provided that the Pokémon has a major status affliction.
Throwing is physical, so yes.