Jerry Douthett of Rockford says Kiko's action helped uncover an undiagnosed diabetic condition and led to treatment that could save his life.
He resisted seeking care until giving in to his nurse wife's pressure one day last month.
Before going for an appointment, Douthett says he went out drinking, then came home and passed out.
When he awoke, the terrier was beside him in bed and lots of blood was where his toe used to be.
His wife rushed him to Spectrum Health Blodgett Campus, where doctors found a bone infection and amputated the rest of the toe.