Electronic noses (e-noses) are new devices designed to mimic the human sense of smell by detecting and recognizing odors and flavors based on the chemical reactions between different sensors and the volatile odorous molecules. Although its use in the field of food and beverage quality, in the control of air pollution, and even in the detection of explosives or narcotics is well documented and largely adopted, its potential use in medicine is still in its infancy. However, preliminary data from several studies performed on patients affected by colorectal and lung cancer have demonstrated that e-noses could play a role in cancer detection and screening. Nevertheless, the difficulties in the calibration of the device, in the interpretation of the data, and the specificity of the information obtained, make the use of the e-noses still far from their applications in the routine clinical practice.