Ash (Satoshi)'s starter Pokemon was going to be Clefairy (Pippi) but was swapped for Pikachu to make it appealing for boys and girls alike.
Upon being told that Pokémon was going to be shown worldwide, director Masamitsu Hidaka decided to phase Brock out of the Orange Islands season, fearing American audiences would perceive him as a racist stereotype towards Asians. However, when his character received strong positive reception, he was brought back into the series.
In the English dubbed version there have been notable fourth wall breaks by characters. In season 1 episode 26, when Gloom unleashes a foul odor everyone is repulsed, including Meowth. When Jesse points out that Meowth lacks a nose, Meowth says 'the cartoonist must have forgotten to draw it on!' Also, in season 1 episode 27, when Team Rocket attempt to steal Drowzee and Hypno using a convoluted mechanism which fails, they just grab them using whips. When Jesses asks why they didn't do that first, James says that they have to somehow make the show 30 minutes long.
The names of Jessie and James of Team Rocket were changed from their original Japanese names due to cultural reasons. In Japan, they are known as Musashi (Jessie) and Kojiro (James), which is a literary reference to two rival Samurai.
The "outlaw puns" from the Team Rocket villain names (Jessie and James, Butch and Cassidy, Annie and Oakley, etc.) only exist in the English version.