Josh Kirby: Time Warrior! Chap. 5: Journey to the Magic Cavern (1996)

Time-traveling youth Josh Kirby, scientist Irwin 1138 and teen warrior Azabeth Siege are trying to keep a powerful device called the Nullifier away from evil Dr. Zoetrope. But they've hit a snag, having landed on a planet occupied by a race of mushroom people and seen Azabeth become ill upon eating a poisonous plant. They then search for the antidote, while also avoiding the many potential dangers surrounding them.