Ammonia is an extremely irritating odor. Ammonia is a compound of nitrogen and hydrogen. It is a colorless gas with a characteristic irritating odor and is a common nitrogenous waste product. Especially in aquatic organisms, it makes a significant contribution to the nutritional needs of terrestrial organisms by serving as a prerequisite for food and fertilizer. Ammonia is also, directly or indirectly, the basis for the synthesis of many pharmaceuticals and is used in many commercial cleaning products. Ammonia is a chemical that occurs in trace amounts in nature and is produced by nitrogenous animals and plants, and small amounts of ammonia and ammonia salts are also found in rainwater. In the human body, ammonia is produced by the breakdown of proteins. If a person perceives an ammonia odor in his or her own body, such as in the mouth, it is a sign that the body is suffering from certain diseases. If ammonia is present in the mouth, it reflects a kidney disease. If renal insufficiency or renal failure is present, it is recommended that patients seek medical attention and do relevant tests to avoid delaying their condition.