Some of the sweat glands are located in the external auditory canal, armpits and groin. The ceruminous glands in the external auditory canal evolved from the sweat glands, and the secretions of the ceruminous glands mixed with the detached epithelial cell debris of the ear canal to form what is commonly known as earwax. There are individual differences in whether sweat glands and ceruminous glands produce abundant secretions. The secretions of sweat glands are mainly fatty acids, which are broken down by bacteria on the surface of the body and turned into a variety of unsaturated fatty acids, together with the accumulation of metabolites and necrotic epithelial cells, which results in a bad smell or odor, which is why earwax smells bad. If the ceruminous glands in the external ear canal secrete a lot of earwax, you may have “greasy ears”, and there will be a lot of earwax, which may even block the external ear canal and affect your hearing, or the ear canal may often have “pus”. If the sweat glands in the armpits are hypersecretory, then there will be the manifestation of fox odor. In outpatient clinics, we often treat patients who have a lot of earwax and smell a mild or heavy odor, especially in the hot season, or some people admit to having bad breath after a medical history. Why is earwax a close relative of bad breath? Because the gene that controls sweat glands and cerumen glands in us humans is located at base 538 on the ABCC11 gene in the middle of chromosome 16. Now you understand! Why do some people have drier earwax and some people don’t have bad odor? With the evolutionary evolution of human beings, the above genes have undergone mutations resulting in reduced sweat gland secretion and decreased secretion, in fact, most of us are fortunate enough to be able to avoid bad odor because we benefit from the genetic mutations. If we have more earwax in the external auditory canal, we must go to a regular hospital ear, nose and throat for ear cleaning, usually pay attention to keep clean and hygienic, try not to go digging, not to mention some clubs to go picking ears, so as not to secondary otitis externa, especially fungal otitis externa, fungal otitis externa in recent years the incidence of outpatient clinic has increased significantly, this kind of patients have the bad habit of digging the ear.