'He's my hero' - Boy, 4, saves mum's life after she has severe allergic reaction to ice cream

An Auckland mum says her young son is "a hero" after he helped save her life when she had an anaphylactic reaction.

Michelle Woods was driving her sons, Mylo, 8, and Leo, 4, down Dobell Rd in Stanmore Bay on Friday evening when she began developing severe allergic symptoms.

But quick-thinking Mylo sprang into action and made sure his mum received the medical attention she needed.

She believes eating a dairy-free sorbet, bought from an ice cream parlour, that had been contaminated with milk was the cause of the reaction.

Miss Woods bought three sorbets, one for each of them.

She asked for all three to be dairy-free but only emphasised her own reaction.

"I was pretty specific that mine be dairy-free, but then I had some of my sons' and I think maybe there was some contamination.

"People don't ever seem to appreciate the effect it can have if they cross-contaminate."

As Miss Woods felt herself become sluggish and pulled the car over, Mylo knew exactly what to do.

He flagged down a man running past with his dog, calmly explaining his mum's predicament.

The man administered Miss Woods' EpiPen before things got worse.

The humble young saviour is quick to deflect any grandiose praise for his achievements.

"I keep calling him my hero but he just [shrugs] it off," Miss Woods said.

Passerby Jennifer Kinsella was on hand to call an ambulance for Miss Woods, and also praised Mylo.

"The little boy was an absolute star. He was amazing."

Once the ambulance arrived, Miss Woods was given adrenaline and began her recovery.

She is thankful for all the assistance she received.

"It's a fantastic community ... people are always doing things to help others."