Ozzy & Drix
Phil LaMarrOsmosis Jones (voice)
Jeff BennettDrix (voice)
Alanna UbachMayor Paul Spryman / Hector's Mom (voice)
Justin CowdenHector Cruz (voice)
Tasia ValenzaMaria Amino (voice)
Jim CummingsPolice Chief Gluteus (voice)
Rob PaulsenTravis Lum (voice), Stickety Lipid (voice), Backseat / Travis Lum (voice)
Vivica A. FoxEllen Patella (voice)
Pat FraleyPnuemoniac (voice), Nerve Cell General (voice), Brain Advisor #1 (voice)
Frank WelkerBilly Blob Bile (voice), Tar (voice), Dander (voice)
Charlie AdlerAbglobtus Goop (voice), General Malaise / Dr. Hammertoe (voice), General Malaise (voice)
Jeffrey TamborThe Mole (voice)
Kimberly BrooksChristine Kolchuck (voice)
Kevin Michael RichardsonRescue Cell (voice)
Cree SummerMayor Santorini (voice)
Tim CurryNick O'Teen (voice), Scarlet Fever (voice)
Tara StrongAshley / Carbon Monoxide (voice), Jenna (voice)
Brad GarrettStrepfinger (voice)
Dawnn LewisCilia Tyson (voice)
Joe LalaHector's Dad (voice)
Jim BelushiCaptain Quinine (voice)
Kath SoucieNaurine / Celly Katz (voice)
Andrea MartinAunti Histamine (voice)
Candi MiloMumsy Glop (voice)
Miriam FlynnDrixeen (voice)
Neil RossCop (voice)
Justine BatemanRota (voice)
Billy WestMuscle Cell (voice)
Danny BonaduceSmirch (voice)
April WinchellCafeteria Lady (voice)
Wendie MalickNumber 2 / Sticky Flagella (voice)
Jess HarnellShwee (voice)
Julian SandsPenicillin G (voice)
Rino RomanoJude (voice)
Danny MannRudy (voice)
Roger RoseJumbo (voice)
Henry WinklerSal Monella (voice)
Brian PosehnSylvian Fisher (voice)
Kathy NajimyLoretta Epstein (voice)
Danny CookseyShane (voice)
Hope LevyBrittany Estrogen (voice)
Jeffrey GarciaRicardo Amino (voice)
Dee Bradley BakerFather Glop (voice)
Susan SiloCryo (voice)