Blood inside the mouth when spitting or spitting or bleeding when brushing the teeth or when chewing on an apple is mostly due to a wound inside the mouth. There are several causes of wounds, as follows: First, it is an exogenous irritation, such as food, fish spines, or something that cuts the mucous membrane, or wounds caused by tooth extraction, but this kind of wounds are usually clearer, and the patient can have a very clear judgment. Second, there are relatively small endogenous wounds, due to gingivitis or periodontitis, resulting in localized gross blood vessels are very brittle, resulting in bleeding under very light external force, or even sip or spit a little bit may have a small amount of bleeding, this kind of bleeding will not be a lot of bleeding, are due to gingivitis or periodontitis. Third, there are some systemic systemic diseases, such as leukemia will also appear spontaneous gum bleeding, the amount will sometimes be slightly more. Specific causes are not recommended to give a qualitative answer on the network, because the feedback is too little information, there is no way to make a very accurate judgment, it is recommended to go to the hospital at the first time to do the appropriate examination, to clarify the cause of the disease. According to the symptoms of the appropriate treatment, do not scare yourself, random diagnosis is not scientific enough.