Bleeding in the mouth in the morning, along with a bad smell, is most commonly caused by gum infection or gum inflammation due to plaque and tartar buildup around the teeth. Conditions such as gingivitis or more advanced gum disease can cause bleeding, bad breath, swollen gums, and an unpleasant taste in the mouth. Poor oral hygiene, smoking, dry mouth during sleep, tooth decay, mouth infections, vitamin deficiencies, diabetes, or stomach acid reflux can also contribute to these symptoms. In some people, bleeding may occur from brushing too hard or from infected gums that bleed easily during the night. Maintaining good oral hygiene is very important, including brushing gently twice daily with a soft toothbrush, flossing carefully, cleaning the tongue, drinking enough water, and avoiding tobacco products. A professional dental cleaning may be needed if tartar has built up around the teeth. Eating foods rich in vitamin C and maintaining a healthy diet may also support gum healing. If the bleeding continues, or if you have loose teeth, pus discharge, severe gum swelling, mouth ulcers, fever, or persistent bad breath despite cleaning, you should visit a dentist for a detailed examination and treatment. Early treatment usually helps control the infection and prevents further damage to the gums and teeth.