Brief Answer:
Blood mixed saliva could be due to various causes.

Detailed Answer:
Hi

Thanks for posting the query. I do understand your concern, I'll try my best to help you with this problem.

Blood tinged saliva could be due to various reasons such as:
1. Bleeding gums secondary to gingival inflammation.
2. Dry mouth, secondary to mouth breathing.
3. Blood from the nose or sinuses can mix up with salivary secretions.
4. Increased blood pressure on lying down can cause rupture of the weak blood vessels in the upper respiratory tract.

A complete examination of the nose and the throat is required to identify the exact cause of the bleeding.

Till you consult your doctor you may try the following home remedies:
1. Drink adequate warm water to keep the mucosa hydrated.
2. Use saline nasal spray to keep the nasal mucosa moist and prevent mouth breathing.
3. Raise the pillow so as to reduce the blood pressure to the skull.
4. Avoid mouth washes for few days. Mouth washes may dry up the mucosa of the oral cavity causing bleeding.

Hope I have answered your query; I'll be available for the follow up queries.

Regards
Dr. Naveen Kumar N
ENT and Head & Neck Surgeon

---