Sabrina: The Animated Series - Season 1 - Eps 26: Witchitis
Harvey has to get his measles shot and Pi starts to tell scary stories about getting shots from doctors. Sabrina boost his and her own confidence about getting shots, but when Hilda and Zelda take her to get a witchitis shot Pi's scary stories start to get to her and she eventually catches it from a magic cactus. Witchitis causes her magic to act wacky and makes her feel awful. Salem discovers that if she doesen't get the shot it can result to Hypogermia and when she catches it she finally gets her shot but has to pay a huge doctor's bill for the delay.
About Sabrina: The Animated Series

Title: Sabrina: The Animated Series
First Air Date: 1999-09-06
Last Air Date: 2000-02-27
Status: Ended
Rating: 6.7/10 (from 78 votes)
Language: ZH
Seasons: 2
Total Episodes: 65
Network: ABC UPN
Genres: Animation, Sci-Fi & Fantasy, Comedy, Family
Production Companies: Riverdale Productions, DiC Entertainment, Hartbreak Films, Cookie Jar Entertainment, Savage Studios
Synopsis
An animated prequel to the live-action show "Sabrina, the Teenage Witch," the series features 12-year-old Sabrina Spellman, who's half mortal and half witch. Though few people know of her powers, and her mortal uncle frequently warns her not to use her magic to solve problems, Sabrina still borrows spells from the Spookie Jar and gets into trouble with her friend Harvey.
Cast

Melissa Joan Hart
Hilda Spellman / Zelda Spellman (voice)

Nick Bakay
Salem Saberhagen (voice)

Emily Hart
Sabrina Spellman (voice)

Jay Brazeau
Uncle Quigley (voice)

Jason Michas
Slugloafe (voice)

David Sobolov
Spookie Jar (voice)

Chantal Strand
Gem Stone (voice)

Cree Summer
Chloe Flan (voice)

Bill Switzer
Harvey Kinkle (voice)

Bob Bergen
Tim (voice)