How can I heal an intestinal infection causing bad breath?

See your health care provider as soon as possible ( doctor or dentist).
Poor dental hygiene and smoking cause most cases of bad breath in adults.
Infections of the mouth and sore throat infections may also cause bad breath. Recently it has been suggested that bad breath is occasionally due to gases absorbed from the intestine and released through the lungs. Unfortunately, even if this is correct, it isn’t clear what can be done about it.
Finally, unusual problems such as abscess of the lung or heavy worm infestations have been reported to cause bad breath, although we haven’t seen these in our practices.

The doctor will thoroughly examine the mouth and the nose. A culture may be taken if the patient has a sore throat or mouth sores. Antibiotics may be prescribed. If there is an object in the nose, the doctor will use a special instrument to remove it. See your doctor, if you suspect an intestinal infection.

Proper dental hygiene, especially flossing, and avoiding smoking will prevent most cases of bad breath. If this doesn’t eliminate the odor, a visit to the doctor or dentist may be helpful.
Mouthwashes are of questionable value. Don’t use mouthwashes that simply perfume the breath. These cover up but don’t treat the underlying problem. And good luck.