Kacper Krauze, 13, went into shock while paddling with pals in a freezing river.
He vanished below the surface for 25 minutes and after being dragged lifeless from the water his heart had to be restarted in an air ambulance.
Kacper remained in a coma for nine days despite the efforts of doctors and his family to bring him around.
Nothing worked – until his mum Wioletta, 43, took in his favourite Lynx Black deodorant to freshen him up.
As soon as he smelled the fragrance he opened his eyes. He is now on the road to a full recovery.
Wioletta said: “A nurse had suggested I bring in some of his toiletries to wash him with. As soon as I sprayed the Lynx he opened his eyes immediately.
“He must have remembered that was his favourite smell. I just couldn’t believe it.’’
Kacper got into difficulties in a shallow stretch of the River Eden near the family’s home in Appleby-in-Westmorland, Cumbria.
He said: “I have always absolutely loved Lynx.
“It’s my favourite smell.”