The most common cause of bleeding gums is gingivitis i.e. inflammation of the gums. When plaque is allowed to collect on the teeth, the bacteria in them destroy the healthy gum tissue thus causing the gums to get inflamed and irritated which in turn leads to bleeding from gums. If left untreated, the plaque forms a harder layer known as tartar which can lead to further destruction of gums and lead to periodontitis and loss of bone around tooth, eventually leading to tooth loss. Periodic cleaning of teeth is advised to prevent these conditions.

Apart from gingivitis, the other causes of bleeding gums to name a few are vit. C, vit.K  deficiencies, leukemias, bleeding disorders, improper flossing, use of blood thinners, etc.