Dark Gums: What They Can Mean, When They Are Normal and When to See a Dentist

By Dr. Cléo Salustiano · CRO-SP 170844

08 Nov 2026 · 8 min read

Updated 08 Nov 2026

Dark gums are most often natural pigmentation caused by melanin, the same substance that gives skin its color: it is common in people with darker skin, appears on both sides of the mouth, has been there for a long time and does not hurt. Other frequent causes are smoking, some medications, amalgam fillings and crowns with metal. A new, isolated dark spot that grows, changes color or shape, becomes raised or bleeds, however, should be examined by a dentist, even if it does not hurt.

Healthy gum color varies a lot from person to person, from light pink to brown. So "black gums" are not always a sign of disease. What helps tell them apart is how long the color has been there, whether it is the same on both sides, whether there are other symptoms (bleeding, swelling, pain, bad breath) and whether there is a related factor, such as smoking, a new medication or a recent filling or crown in that area.

Dr. Cléo Salustiano (CRO-SP 170844), a dentist in Mooca, explains the most common causes of dark gums, the signs that call for an assessment and what can be done when the concern is only cosmetic.

This article comes from Dr. Cléo Salustiano's dental office in Mooca, São Paulo (care in English, Portuguese and Spanish). See the gum health page to learn how the treatment is done here and book your assessment.

Main causes of dark gums

Physiological pigmentation: this is the most common cause. The cells that produce melanin are also present in the gums and, in some people, produce more pigment. The color is usually brown or dark brown, in bands or patches on the front gums, on both sides, symmetrically, and often matches the skin tone. It is not a disease, does not turn into one and needs no treatment. If it bothers you when you smile, it becomes a cosmetic question.

Smoking: tobacco stimulates melanin production in the gums, causing what is called smoker's melanosis, most visible on the front gums, especially in the lower arch. After quitting, the pigmentation may lighten gradually over months or years. Smoking also reduces gum bleeding and can hide signs of gum disease, so smokers need regular checkups even without symptoms.

Medications and general health: some medications can cause pigmentation in the mouth, such as certain antimalarials, some long-term antibiotics, some chemotherapy drugs and hormone treatments. If you noticed the change after starting a medication, talk to the doctor who prescribed it and do not stop it on your own. More rarely, a new, diffuse darkening of the mouth together with darker skin, tiredness, weight loss or low blood pressure may be linked to hormonal problems, such as adrenal gland disorders, and needs medical investigation.

Fillings, crowns and teeth: an amalgam tattoo is a flat, painless blue-gray spot caused by particles from a silver filling left in the gum, usually near an old filling, after an extraction or a root canal. It is harmless, and an X-ray can help confirm it. Older porcelain-fused-to-metal crowns can leave a dark line at the gum edge, because the metal shows through or the gum has receded. A tooth that darkened after trauma or a root canal can also make the surrounding gum look grayish. Bruises from a knock, hard food or aggressive brushing can leave the gum purplish for a few days.

When to see a dentist and what can be done

Have it checked if the spot is new, appears in just one place, grows, changes color or shape, has irregular borders, becomes raised, bleeds or turns into a sore. In the vast majority of cases the cause is benign, but pigmented lesions in the mouth, though rare, can be serious, and an exam is the only way to know. The dentist examines you, asks about your history and, when needed, requests tests, performs a biopsy or refers you to another professional. A useful tip is to take well-lit photos of the spot to compare over the weeks.

Dark gums can also be inflamed gums. In gingivitis and periodontitis, the gum becomes dark red or purplish, swollen and bleeds when brushing. Grayish gums with sores between the teeth, strong pain, easy bleeding and intense bad breath may indicate an acute infection that needs prompt care. If you have a fever, swelling spreading across the face or difficulty swallowing or breathing, go to an emergency room. The article swollen gums: what to do describes these conditions.

When the cause is an old filling or crown, the dentist assesses whether it is worth replacing it with a metal-less material, considering the condition of the tooth and gum; the article when to replace an old filling helps explain that decision. When the pigmentation is natural and bothers you cosmetically, there are gum depigmentation techniques, but they are only recommended after assessing the gums, the smile and your expectations, and the color may partly return over time. For smokers, quitting is the first step. Do not use whitening products, acids, rubbed baking soda or home remedies on the gums: they irritate and can injure the tissue.

This content is for information only and does not replace an exam. Consult a dentist whenever you notice a new or different spot on your gums. In Mooca, Dr. Cléo Salustiano sees patients every day, from 8 a.m. to 10 p.m., including Sundays and holidays, for gum health and general dentistry.

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