Uwe Friedrich, a dog trainer, said that these dogs receive training at a special school; their coaching is based on positive stimulation. The smell of cancer is regarded as lucrative, positive by these dogs. Over 200 breath samples are placed in front of the dogs and they have to sniff out those with cancer and those without the disease.  

Lung cancer has a particular kind of odour combination, making it easy for dogs to detect it. On top of it, they can also differentiate between patients who have been suffering from the disease for quite sometime and those who have just contracted the disease. This is not all, studies show that dogs can also detect bladder and colon cancers. In addition to this, they can also sniff out low blood sugar level in a diabetes patient.