You must be talking about the episode where ash and tracey get sick from a poisonous Pokemon and that episode is called the stun spore detour
if you are looking for the name it was somthing like ash gets sick but I don't really remamber. *UPDATE 8-29-12* The episode is called "A Better Pill to Swallow"
Ash battled Norman in the episode "Balance of Power."
the second episode.
In the episode Trees a Crowd.
episode 56