I keep having a bad taste in my mouth even when im not eating or have eaten anything. What is that?

Unhappy mouth? How happy is your mouth (teeth, gums, tongue)? Brushing (even your tongue!) and flossing regularly can help. What's dripping from upstairs? Nasal drip from allergies or chronic sinus infection can taste icky. Anything from downstairs? Acid reflux from your stomach? These are all good things to talk with your doc about. Good luck.
See a dentist. In the majority of cases, the cause of bad breath, or halitosis, is the product of bacteria in the mouth and gum disease. The proper diagnosis is the key to a successful treatment. See your dentist for Halimeter test, diagnosis and bad breath treatment that depends on its cause. Good luck.
Many causes. Some of the more likely ones are gum disease, poor oral hygiene, infection, post nasal drip, gastric reflux or decaying teeth. See your dentist for a complete and thorough exam.
Dental check up. Is what you need to make it sure you don't have any oral infection. If periodontal disease or decay is ruled out, see an MD.