Ellery Queen (1975)

S1E6 The Adventure of Miss Aggie's Farewell Performance

Vera Bethune, cherished for her role as Miss Aggie in a popular radio soap opera, faces being written off the show. In a shocking turn of events, she drinks from a jug that has been poisoned in a murder plot against her. Though she ends up in the hospital, where she manages to pull through, the assailant is still on the loose and determined to finish what they started.