Murder in Texas (1981) with Sam Elliott as Dr. Hill. He laced her pastries with crapola and when she was very sick, gave her a hypo filled with poop to speed things up.
Sick, sick puppy.
I saw that, but Sam Elliott was not the one to play Dr. Hill. The real Dr. Hill was blond, slick, and a cool cucumber. Elliott's voice is too low for that part.