Gums that bleed when brushing are a common symptom. In most cases, it indicates gingivitis or the start of inflammation. Bacteria irritate the gums, which causes them to bleed. If the gums are swollen, red or painful, this is most likely the case. However, brushing too hard or using the wrong technique can also cause bleeding. Always use a soft brush and avoid scrubbing. Bleeding gums are a signal not to be ignored. Visit a dental hygienist or dentist for an assessment. With good care, the gums usually recover within a few days. Prevention is better than cure: brush twice a day and clean between your teeth.
Periodontology - Symptoms and Diagnosis
Is bleeding when brushing always a sign of inflammation?
Usually it is, but it can also be caused by brushing too hard.