Bad breath in the morning is a common problem that affects many people. Apart from poor oral hygiene, the most common cause of the problem is dry mouth at night. Also, eating spicy foods before going to bed can be the culprit. However, in rare cases, bad breath is a lesser-known sign of killer cancer. According to the National Health Service of Great Britain, bad breath is a symptom of throat cancer. This condition is more common in people over 60 and is more common in men than women.

Bad breath is on the list of possible symptoms of throat cancer. According to the University of California at San Francisco, this sign is more likely to appear in the later stages. "As the tumor grows, it can cause pain, weight loss, bad breath and swallowing problems," say doctors. The main symptom of laryngeal cancer is hoarseness that lasts more than three weeks, and other symptoms include difficulty swallowing or pain when swallowing, a lump or swelling in the neck, prolonged cough, shortness of breath, persistent sore throat or ear, difficulty breathing, extreme fatigue and unintentional weight loss. It is not known exactly what causes laryngeal cancer, but it is known that smoking, regular consumption of large amounts of alcohol, a family history of laryngeal cancer, an unhealthy diet low in fruits and vegetables, and exposure to certain chemicals and substances such as asbestos and coal dust can increase the risk.