|Dr. Kvetch in Episode 1599.|
He appeared later in Episode 2630, now diagnosing Oscar's niece Irvine with the same infliction. Dr. Kvetch prescribes rest, fluids, and staying away from nice people. He re-appears at the episode's end, when Oscar is now infected with the Grouch Flu. However, the doctor flees the scene, fearing for his own safety.
In Episode 1599, Kvetch appears as a gray Grouch, recycled from the same puppet used for Othmar and Gary Grouch. In subsequent appearances, Kvetch is orange and has white hair and eyebrows, modified from the puppet originally used for Osvaldo, el Gruñón.