Hi! Welcome to Healthcaremagic. I read your query. Do you have any known illness? Or some throat infection? Most probably it could be bleeding from gums, which can be due to gum disease as well as some systemic disease. Do you notice plaque or calculus on your teeth? Get oral prophylaxis done. Dental check can confirm if you have gum bleeding or not. Brush twice daily. Use mouthwash with tannic acid. Take healthy diet, multivitamins and minerals. If bleeding persists, see a physician and get blood test done for clotting factors, Hb, chest xray, etc. At times throat irritation may cause blood on spitting. Hope the answer helps you. Thank you!