Spitting blood in the morning but not during the day is often due to mild and manageable causes such as minor gum irritation or inflammation, dry mouth, or nasal irritation. Overnight dryness and minor gum issues can cause small amounts of bleeding that show up when waking and spitting in the morning, but clear up during the day as saliva production increases and the mouth rehydrates. Other common causes include gum disease like gingivitis, minor oral injuries, or teeth grinding during sleep. These conditions typically cause localized bleeding that is worse in the morning and does not persist throughout the day. If the bleeding is frequent, heavy, or accompanied by other symptoms, it is important to see a dentist or doctor for evaluation, as it could indicate more serious dental or systemic issues.