Why Do My Gums Bleed When I Floss?

Why gums can bleed during flossing

Bleeding can occur when you start a new flossing routine, according to the American Dental Association’s MouthHealthy guide. It can also be a sign of gingivitis, the early stage of gum disease. Plaque that builds up around the teeth can inflame the gums. You may also notice redness, swelling, or tenderness.

Think about what happened in that spot. Did the floss slip through a tight gap and strike the gum? Have you noticed bleeding at other times, such as when brushing or eating? Share those observations with your dentist so they can examine the area and check for signs of inflammation.

Ease the floss through the gap

Use a gentle rubbing motion to pass the floss between teeth. At the gumline, wrap the strand around the side of one tooth to form a C. Slide it gently along the tooth surface, then clean the facing side of the neighboring tooth. Keep the movement controlled as you pass through a tight contact.

If the floss keeps catching or cleaning between your teeth hurts, ask your dental team to show you the technique in that spot. Mention any braces or bridges when you ask. They can help you choose a tool that fits the space, such as an interdental brush or a water flosser.

When to contact a dentist

Call your dentist if the bleeding recurs or concerns you, including if it started with a new routine. Mention soreness, swelling, or bleeding during brushing or eating when you call. At a visit, your dental team can examine your gums and may measure the spaces where they meet your teeth.

Ask for urgent dental care if your gums become very sore and swollen or a tooth starts to loosen. Seek emergency care right away if heavy bleeding from your mouth will not stop or severe swelling makes it hard to breathe.

Three details to share when you call

• When it happens. Say when it started, how often it happens, and how long the bleeding lasts.
• Where you see it. Describe the area, such as behind a lower molar, and whether one spot or several are involved.
• What else you notice. Mention pain, swelling, or bleeding outside flossing. Share recent changes to your cleaning routine or medicines, including blood thinners.