The celebrated TV chef joined Nova's Fitzy & Wippa on Wednesday afternoon, where she shared that her 12-year-old son Tom was rushed to hospital.
She had been in the kitchen, baking, when she heard him scream.
The mum-of-two discovered he'd had a trampoline accident.
"I was doing muffins," the 47-year-old told them.
"And then I hear a bit of a scream and of course, I am not watching them on the trampoline. Anyway, he really, really hurt his neck so badly. Then I have to say 'How bad's the pain?' We go through the whole parenting thing."
The Aussie personality, who is mum to two sons who she shares with her ex-husband, Bill Wilson: Angus, 15, and Tom, 12, joked that she wasn't too concerned.
"Can you hurry? I can't spoil my baking, it'll put me behind," Hay told the hosts.
"Anyway, long story short: ambulance. Paramedic," she explains. "My son explains what's happening -- he can't move ."
Hay realised she'd given Tom medication that was for people aged 14 and up.
The paramedic then questioned Hay about how Tom injured himself.
"I'm like, 'Well I didn't really see it because I was cooking... would you like a muffin?'" she admitted. "I didn't just offer him one, I then took off to the kitchen and wrapped one up for him, just to escape the whole thing."