Halitosis described as a rotten egg smell or sulfur smell is medically caused by volatile sulfur compounds. Substances such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide are the main causes; when produced in the oral cavity or digestive system, they pass through the lungs and are exhaled through breathing, giving off a characteristically unpleasant odor. Many people overlook the fact that this smell is not just an oral hygiene issue, but can also serve as an important indicator of systemic disease, especially liver hypofunction.
Modern medicine views the liver as such an important organ responsible for various metabolic and detoxification functions that it is called our body's chemical plant. It detoxifies ammonia, the end product of protein metabolism, and breaks down drugs or toxic substances to excrete them from the body. However, when liver hypofunction occurs, this detoxification ability drops significantly. Toxic substances generated inside the body or toxins entering from outside are not processed properly, enter the bloodstream, and are ultimately exhaled through the lungs with the breath, causing foul halitosis. In particular, volatile sulfur compounds generated during proteolysis must be metabolized in the liver; when liver function weakens, they can accumulate in the body and manifest as halitosis.
In addition, liver hypofunction affects the overall digestive system. The liver produces bile to help digest fat, and if a problem arises with bile secretion, indigestion can occur. When undigested food residues stay in the intestines for a long time, it leads to an imbalance of the gut microbiota, known as dysbiosis, and volatile sulfur compound production increases particularly due to the proliferation of sulfur-reducing anaerobic bacteria. Problems such as small intestinal bacterial overgrowth or delayed gastric emptying can also cause rotten egg halitosis. All of these problems are complex phenomena that are either closely linked to the liver or appear as results of liver hypofunction. In its early stages, liver disease has no distinct symptoms and the liver is called a silent organ, but subtle changes like breath odor can be an important early warning sign, so you should listen to your body's voice rather than brushing it aside.
