Gums bleed when brushed?

Keep brushing. See Brushing Teeth for brushing help. Bleeding is usually caused by poor brushing and plaque accumulation, which leads to gum inflammation (yellow arrows) and bleeding.
Try using a soft-tip bristle toothbrush. For those who have arthritis, consider using a soft bristle on an electric toothbrush.
If it doesn’t stop in a couple days, make a dental appointment. A dentist will evaluate the teeth and decide what type of treatment is needed.
