Brushing your teeth and vomiting blood, but not when you don’t brush your teeth, may be due to gum inflammation, periodontitis, blood diseases and so on. 1. The most common reason for brushing teeth and vomiting blood that is not normally present is inflammation of the gums, mainly due to the presence of more bacteria and calculus around the teeth, which stimulate inflammation of the gums. If you suffer from gingivitis, periodontitis, the gums will appear obvious redness and swelling, become fragile and easy to bleed. 2. Blood diseases such as leukemia will be manifested as very fragile gums, brushing teeth and other touch gums may bleed. There may be other reasons for brushing teeth and vomiting blood, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.