When you open your mouth and find it, be careful as it may be a sign of cancer

Many people believe that the unpleasant odor people exhale is caused by oral disease or forgetting to brush their teeth in the morning. However, modern medicine has proven that many systemic diseases, such as liver, lung, kidney, and stomach diseases, can also cause bad breath. If it occurs frequently, you should look for the cause.

Rancid odor - lung cancer

Lung infection, bronchitis, lung abscess, chronic tracheitis, pneumonia, emphysema and even lung cancer can cause bad breath to varying degrees. These odors are mostly caused by mucus that accumulates in the lungs. Among them, patients with lung abscess often have rancid bad breath. Such patients often have fever, purulent sputum, etc., and chest X-ray examination can generally confirm the diagnosis; patients with hemoptysis due to tuberculosis and hemoptysis due to bronchiectasis often have bloody bad breath; patients with advanced lung cancer often have rancid odor in their mouth and exhaled breath.

It is worth mentioning that smokers often have a kind of bad breath that is easily recognizable. Even if he doesn't smoke, others can tell that he is a smoker by his bad breath. This type of bad breath is caused by smoke that remains in the anatomical dead space of the lungs and is gradually exhaled as the smoker breathes, producing bad breath with a "smoke smell". When smokers also suffer from lung diseases, the odor may be more pronounced due to the further increase in the dead space volume and even the generation of pathological dead space.

Putrid smell – upper respiratory tract disease

Upper respiratory tract diseases such as sinusitis, tonsillitis and pharyngitis will secrete a large amount of protein-containing mucus, some of which forms nasal mucus and the rest flows from the nasal passages into the oropharynx. Some of this mucus adheres to the back of the tongue or the oropharynx, and when the protein breaks down, it produces a putrid smell.

Sour smell – stomach problems

When the pyloric part of the stomach is narrowed or obstructed, food stays in the stomach for too long and produces a sour, smelly, and rotten odor that is emitted through the mouth. Gastric diseases such as reflux esophagitis can also cause pathological bad breath, and the vomitus adhering to the mouth and throat will continuously release "sour gas". Usually, bad breath can be significantly improved after active treatment of stomach problems.

Rotten apple smell - diabetic pyruvic acidosis

When a person's blood sugar level is too high and not under control, the fat in the body breaks down and produces ketone bodies, the α-ketoglutaric acid in which emits a sour, rotten apple smell. When this odor is exhaled, the ketone body concentration in the patient's body is already very high, close to or reaching the level of diabetic ketoacidosis. Medical attention is needed promptly, otherwise there will be a risk of life.

Urine smell - uremia

The foul smell of urine is mostly emitted by patients with chronic nephritis or kidney disease. When the disease progresses to the stage of chronic renal failure (commonly known as uremia), due to anuria, certain toxic substances cannot be excreted from the body and are retained in the blood, which will cause the patient's exhaled gas to emit a urine smell. This is a signal that the condition is becoming critical.

Foul-smelling stool – liver failure

When liver failure occurs, the liver's metabolic capacity weakens and its ability to break down toxins decreases, leading to increased blood ammonia and a slightly sweet excrement odor in the mouth, also known as the "breath of death." The body's ability to metabolize certain branched-chain amino acids is weakened, which can also lead to a rotten apple smell.

In addition, some bad breath is caused by psychological illness, such as anxiety, insomnia or certain mental illnesses caused by autonomic nervous system disorders.