Lung cancer, a notoriously hard-to-diagnose and deadly disease, has a new enemy: dogs! German researchers have discovered that they can actually smell it on your breath.

The Schillerhoehe Hospital collected breath samples from 220 volunteers and presented them to a group of specially trained dogs. The dogs detected 75 percent of the samples from people with lung cancer, and 372 out of 400 samples that were cancer-free, according to a study published in the European Respiratory Journal.

But how do they do it? What the dogs smelled were "slight changes in the volatile organic compounds (VOCs) that humans give off when they exhale." So the next time your dog showers you with a faceful of kisses, it might just be because he's trying to tell you that you have lung cancer! Who's a good little doggie diagnostician? Yes, you are! Yes, you are! [, photo via Shutterstock]