http://news.bbc.co.uk/1/hi/magazine/6919063.stm

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A woman in Wiltshire said her Chihuahua detected her breast cancer on three occasions, while a Dalmatian kept smelling a freckle that the owner discovered was a malignant tumour.

The work of dogs in epilepsy is more advanced. The charity Support Dogs has provided 45 seizure alert dogs to epileptics such as Tony Brown-Griffin, 35, from Kent.

Twelve years ago, prior to her getting her first alert dog, she was suffering 12 major seizures a week and countless minor ones, so was housebound and childless. Now she is independent and a mother of two.

Ajay, a golden retriever, licks her left hand 40 minutes before a major seizure, which only happens twice a week now, so she can get herself out of harm's way.

"It's a major stress reduction. I don't have to worry about epilepsy at all unless my dog alerts me. Before I was thinking 'Do I have time to cross the road, will I have a seizure?'"

But neither Tony nor her husband knows exactly how Ajay is doing it, because the slight changes in Tony's behaviour prior to a seizure are imperceptible to them.

"He doesn't get a crystal ball and headscarf and say 'I predict you will have one three weeks on Tuesday' but whether it's a change in blood pressure or body temperature or whether I sweat or smell differently, or a combination of things.

"In the early days it was very difficult to go with the dog because I would feel so well but he was 100% accurate, 100% of the time."

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(Sorry if this has been posted before, I just found out about it today.)