Why do my gums bleed when I brush?: Dr Anne Heelan, Dentist
Gums that bleed when you brush your teeth - normally it's actually caused by the fact that the gums are inflamed, and that plaque is not being sufficiently removed, on a daily basis. And when you do go to then brush them thoroughly, the gums bleed.
So it's a good idea to visit your dentist, and for your dentist to look at your gum health, and to help you change your brushing technique. Only very occasionally, gums bleed because of overzealous brushing. It's normally actually insufficient brushing and stagnant plaque causing the inflammation that causes the bleeding.