Errata » Drowzee
For purposes of proper Pokémon names, treat all cards referring to "Drowsee" as "Drowzee". For example, you cannot have four "Drowsee" plus four "Drowzee" in your deck.
Source: PUI Rules Team (2004-09-02)

Relevant cards

Note: All applicable cards may not be listed below.
EX6_25
EX6_32