David Smith, a British chemical physicist, and Patrick Spanel, a Prague-based physicist, have developed a device that can diagnose ailments from the smell of compounds found in the breath of the afflicted. The device, known as selected ion flow tube (SIFT), was demonstrated at a recent meeting of the American Chemical Society held in Boston, USA. SIFT can analyse a puff of breath for trace gases that signal diabetes, kidney failure, ulcers and, possibly, even cancer. According to the researchers, the fishy smell of compounds called amines indicate kidney problem, while the sweet smell of compounds called acetones can mean diabetes. These tell-tale compounds find their way into the breath when they build up in the blood. SIFT has already been scaled down to table-top size ( Science , Vol 281, No 5832).