These amazing dogs can detect bacteria in people's bodies before it turns into a condition called cystic fibrosis.
Cystic fibrosis - sometimes referred to as CF - is a genetic condition which causes damage to the lungs and other organs.
Research by Imperial College London found that the dogs are sometimes better than machines at detecting 'pseudomonas', which are the most cause of lung infection in the disease.
Not only that, but it can also be less expensive to train dogs to do it.
Professor Jane Davies from Imperial College London said: "This is a really exciting development.
"People with CF could ultimately monitor their lung infections from home by sending in samples for the dogs to check."
They're not the only pooches who are carrying out amazing work, though.
Here are some more brilliant dogs doing amazing things to help others. (If you can't see the videos in this article, then click here.)
A university has 'employed' five dogs to help students who are stressed or anxious about exams.
The five Labradors at Middlesex University even have their own staff identity cards.
It's thought having a dog or another pet in school could help to reduce stress in classrooms.
This next dog Selkie, who is a labrador, is not a trained therapy dog, but she has found a special role in a primary school in Bromley, London.
Pupils and teachers say she has helped children with bereavement and anxiety issues, and has become a valuable part of the school.
One pupil called Charlie, whose mum sadly died, visited Selkie every day as he found she helped him to cope with feelings of sadness.
"It gave me a reason to come into school happy," he said. Great work, Selkie!
Dogs are also frequently used in search and rescue missions, such as this amazing canine hero called Frida.
Frida helped the emergency services find survivors trapped under rocks and rubble after earthquakes in Mexico.
Like the humans on the team, she needed special equipment like boots to protect her feet from sharp rocks, and goggles to protect her eyes from dust.
She used her amazing sense of smell to locate people and the Navy says she's already saved at least 50 lives.
Newsround reported just earlier this year that Frida was retiring from duty after nine years of service.
Denzel is a gorgeous springer spaniel and is trained to sniff out leaks in water pipes underground!
He's able to do this because the water we drink is cleaned using a chemical called chlorine.
Denzel is trained to sniff out that chemical, so when he smells it, it tells the water companies where to investigate.
What a good boy - saving water, one leak at a time!
If you visit a safari park in Kenya, you might see giraffes, lions, zebras and if you are REALLY lucky a rare white rhino. But you might be a bit confused if you saw a 10-month-old Springer spaniel, wouldn't you?
Well, that's exactly where you might spot Drum the dog.
He uses his powerful sniffing skills to prevent people from illegally hunting rhinos.
Drum has been trained by a organisation called Animals Saving Animals to find ammunition and guns used by poachers. What a clever pooch!
And Drum isn't the only dog trained to help other animals.
Train - a 12-year-old Chesapeake Bay retriever in Argentina - is actively encouraged to look for big cat poo!
That's because he uses his super-sensitive nose to search for some of South America's most endangered big cats - for example, pumas, jaguars, ocelots and oncillas.
When Train finds something, he stands next to it and cocks his head. His ears will prick up and he'll wag his tail. He is then rewarded with play time for his good work.
It is hoped that this work will mean that more species of wildlife can be protected in a large area of land that spans the Argentinean, Paraguayan and Brazilian borders.
In 2016, forest fires devastated the land in Chile in South America.
The fire damage left patches that once were thick with old trees, but were then reduced to burnt landscapes.
Three border collies called Summer, Olivia and Daz were brought in to help to replenish it all.
They scampered around the burned forest wearing special satchels to scatter seeds as they ran, which helped to replant trees, grass and flowers.
They could cover more than 30km in just one outing.
Replanting forests while going for a nice long walk? That's excellent multi-tasking for you!
With all these amazing doggos doing good deeds, it's only right that we humans show our gratitude.
That is why a kennel in Missouri in the US has found good way to comfort its dogs, while helping children learn to read at the same time.
Kids aged six to 15 years old have set to work at the kennel, practicing their reading in the company of their puppy pals, to help the animals to feel less anxious.
Dogs in the shelter can sometimes be shy around people, so by getting children to read to them, kennel staff hope that the dogs will be happier in the company of humans.
In turn, it helps the children practice their reading with someone who isn't going to rush them.