Underarm odor can be caused by not bathing for a long time or by bad breath, etc. These causes are not infectious, so underarm odor is not contagious. Common causes of underarm odor include not bathing for a long time, eating smelly food, taking smelly drugs, phenylketonuria, and bad breath. Fox odor is caused by the over-exuberant secretion of sweat glands in the armpits, which produces a large amount of unsaturated fatty acids, and has a certain family genetic tendency, but is not contagious. In summary, the causes of underarm odor are not infectious diseases, there is no so-called infectious source, transmission channels and susceptible people, underarm odor is not contagious, need to actively diagnosis and treatment.