Coco is a life-saver and as far as his owner, Karen Ruddlesden, is concerned, "He's totally changed my world." Karen has Addison's Disease and Coco is the world's first Medical Alert Dog trained to assist an Addison's Disease sufferer.

Addison Disease sufferers do not produce enough steroid hormones and their adrenal glands do not function properly. When the Dorset, England resident's cortisol levels drop, she will have an Addison's crisis, which if not treated quickly, can be fatal. Karan had heard of dogs that were able to assist diabetic owners and wondered if such a dog existed that could help her with Addison's. She contacted the Cancer & Bio-detection Dog organization in Aylesbury, Bucks and Claire Guest, the charity's founder, was happy to take up the challenge of finding such a dog.

Coco was chosen as her medical alert dog and the two have been inseparable ever since. The Chocolate Lab acts as an early warning system and is able to let Karen know when her cortisol levels are dropping, even before she has begun to feel sick. The early warning gives her the time to self-medicate and avoid a trip to the emergency room. The Lab carries Karen's injection kit with him at all times in his vest and has been trained to retrieve the kit on cue.

Coco never leaves Karen's side. He even accompanies her into the bathroom and waits patiently while she bathes or showers. If he detects that her levels are dropping, he will lick her hand and sniff her breath. If Karen does not act on this command, Coco will touch her with his paw and then lick her face. If she is sitting on furniture or lying on the bed, the Lab will climb on the furniture to make sure that she has received his warnings.

"I think it's just amazing that dogs can be trained to do the job that Coco does," says Karen. "I sleep better knowing he will alert me if my levels drop while I'm asleep. I can also relax when out and about knowing that Coco is there to look after me. As long as I have my knight in shining armor with a waggy tail with me by my side, I'm not scared of anything anymore." Coco saves Karen's life everyday by his alerts. He has been able to stop Karen from falling into a coma at least twice a week by detecting her fluctuating levels and retrieving her medical kit.

The Cancer and Bio-detection organization is dedicated to training dogs in the detection and recognition of human disease by odor. These dogs were first trained to detect bladder cancer in humans and have since moved on to Hypo Alert dog for people with hard to control diabetes. "A dog's sense of smell is 100,000 times more powerful than a human's," explains Guest. "We believe they could be trained to help sufferers from a huge range of conditions."

Because of his devotion to his owner, Coco was named a finalist in the Crufts Friends for Life competition which recognizes exceptional life-changing dogs. Although he was not named the winner of the competition, the Crufts Kennel Club Charitable Trust has given 25,000 pounds ($39,946 in US dollars) to the Cancer & Bio-detection Dogs organization.