Trench Mouth (Necrotizing Gingivitis)
Trench mouth comes on fast. Over a day or two your gums get so sore that brushing hurts, they bleed if you touch them, and there's a bad taste and a smell you can't rinse away. If you look closely, the little triangles of gum between your front teeth seem to have been nipped off and covered with a gray film. It feels alarming, but it responds quickly to treatment.
Trench mouth (necrotizing gingivitis, or ANUG) is a sudden, painful gum infection that destroys the tips of gum between the teeth, leaving gray, cratered, bleeding gums and strong bad breath. It's not contagious the way a cold is. Stress, smoking, poor sleep, and a weakened immune system set it up. See a dentist within a day or two. Cleaning and rinses usually bring relief quickly.
Not sure this is what you have? Answer five quick questions in our mouth spot checker. It compares what you see with more than 40 common conditions and tells you how soon to have it looked at.
- What does trench mouth look like?
- Trench mouth meaning and history
- Trench mouth symptoms
- What causes trench mouth?
- Is trench mouth contagious?
- Necrotizing gingivitis vs. necrotizing periodontitis
- Trench mouth vs. other gum problems
- How long it lasts and whether it goes away on its own
- Trench mouth treatment at the dentist
- Home care, step by step
- Over-the-counter options
- Preventing it from coming back
- Pregnancy, kids, and weakened immunity
- When to see a dentist
- FAQ
What does trench mouth look like?
The giveaway is the gum between the teeth. Normally each of those little triangles (dentists call them papillae) comes to a neat point. With trench mouth, the tips die off and leave a flat or scooped-out crater. People often describe trench mouth gums like this:
- "Punched-out" gum tips between the teeth, most often around the lower front teeth first.
- A gray, yellow-white, or dirty-looking film over those craters. This is a layer of dead tissue, bacteria, and fibrin. Wiping it away leaves a raw, bleeding surface.
- A bright red line along the gum edge next to the ulcerated areas.
- Gums that bleed on their own or with the lightest touch.
Ordinary gingivitis makes the gum tips puffy and rounded. Trench mouth takes them away. That's the single most useful difference when you're comparing trench mouth pictures online with what you see in the mirror.
Trench mouth meaning: why it's called trench mouth
The name comes from World War I, when the infection spread through soldiers in the trenches who were exhausted, underfed, smoking heavily, and unable to keep their teeth clean. You'll also see it called Vincent's infection or Vincent's disease, after a French doctor who described the bacteria involved in the late 1800s.
Dentists have used several names over the years. ANUG stands for acute necrotizing ulcerative gingivitis. Today's medical name is simply necrotizing gingivitis, and it belongs to a small group called necrotizing periodontal disease. They all describe the same basic trench mouth disease: gum tissue dying off quickly because bacteria get the upper hand while the body's defenses are down.
Trench mouth symptoms
Necrotizing gingivitis symptoms come on over hours to a few days, not weeks. Experts agree on three hallmark signs:
- Pain. Real, constant gum pain, often bad enough that people stop brushing (which makes it worse).
- Bleeding. Gums bleed easily, sometimes without any touch at all.
- Dead, ulcerated gum tips between the teeth, as described above.
Many people also notice:
- Strong bad breath and a metallic or foul taste
- Extra saliva
- Swollen, tender glands under the jaw
- Low-grade fever, tiredness, or just feeling run down, especially in more advanced cases
A high fever, swelling in the face, or trouble swallowing is not typical of simple trench mouth and needs same-day care.
What causes trench mouth?
Trench mouth isn't caused by one germ you pick up from someone else. The bacteria involved, including fusobacteria, spirochetes (Treponema), and Prevotella intermedia, already live in plenty of healthy mouths in small numbers. The problem starts when something lowers your defenses and plaque has been building up. Then those bacteria invade the gum tissue faster than your body can fight back.
Necrotizing gingivitis causes and risk factors
- Psychological stress. College finals, a new baby, a hard stretch at work, military training. Stress is one of the most consistent triggers.
- Smoking. Most adults who get trench mouth smoke. Smoking reduces blood flow to the gums and dulls the immune response.
- Poor sleep and exhaustion.
- Plaque buildup and existing gingivitis. Trench mouth almost always starts in gums that were already inflamed. Read more about gingivitis and how to reverse it.
- Poor nutrition, including crash dieting or eating very little during a rough patch.
- A weakened immune system, from HIV, leukemia, chemotherapy, transplant or other immune-suppressing medicines, or poorly controlled diabetes.
- A recent illness, such as a bad viral infection.
Most people who get trench mouth stack up several of these at once. A young adult who smokes, is sleeping five hours a night, and has been skipping flossing during a stressful month is the textbook case.
When trench mouth points to something else
Sometimes an otherwise healthy person gets trench mouth with no obvious trigger, or it keeps coming back. In that case we may suggest your physician check some bloodwork, such as a blood count, blood sugar, and an HIV test. That isn't because we expect something serious. Most of the time the results are normal. It's simply the thorough thing to do, because necrotizing gum disease is closely tied to how well the immune system is working. Our pages on HIV and the mouth and leukemia and the mouth cover those connections.
Is trench mouth contagious?
Not in the way a cold or a cold sore is. Medical reviews describe necrotizing periodontal diseases as not transmissible, because the germs involved are common mouth bacteria and what really matters is the person's own resistance. You won't give your partner trench mouth by kissing them, and your kids won't catch it from a shared cup.
The reason it seemed to spread in groups, like soldiers in WW1 or students during exam season, is that everyone shared the same risk factors at the same time. That said, it's still sensible not to share toothbrushes or utensils while your gums are actively bleeding.
Necrotizing gingivitis vs. necrotizing periodontitis
Doctors think of necrotizing gum disease as a spectrum. Where you fall depends on how deep the damage goes:
- Necrotizing gingivitis affects only the gum. The bone underneath is still intact. This is classic trench mouth, and with prompt care the gums can heal well.
- Necrotizing periodontitis means the infection has reached the attachment fibers and bone that hold the teeth. Some of that support is lost for good, and teeth can loosen. It's more likely in people with significant immune problems or after repeated or untreated episodes.
- Necrotizing stomatitis is rare. The dead tissue spreads past the gums onto the inner cheek, lip, or palate. It's mostly seen in people with severe immune suppression or malnutrition.
Trench mouth vs. other gum problems
Sore, bleeding gums have more than one cause. Here's how trench mouth compares with the conditions it's most often mixed up with.
| Trench mouth | Gingivitis | First herpes infection of the gums | |
|---|---|---|---|
| Onset | Sudden, over 1–3 days | Gradual, over weeks to months | Sudden, often after a day or two of fever |
| Pain | Severe | Mild or none | Severe |
| Gum tips between teeth | Cratered, gray film | Puffy and rounded | Swollen, red; tips not punched out |
| Sores elsewhere? | Usually limited to the gums | No sores | Many small blisters and sores on gums, tongue, lips, palate |
| Fever | Mild or none | No | Common, often higher |
| Bad breath | Strong and distinctive | Mild | Can be present |
| Typical age | Young adults | Any age | Young children, sometimes teens and young adults |
| Contagious? | No, not in the usual sense | No | Yes (herpes simplex virus) |
| Treatment | Dental cleaning, rinses, antibiotics if needed | Cleaning and better home care | Comfort care, sometimes antivirals |
A first herpes infection is the one we most need to rule out, since it's treated differently. Our cold sore guide explains how the herpes virus behaves in the mouth.
Other look-alikes
- Desquamative gingivitis. Shiny, red, peeling gums that last for months, often from oral lichen planus or another skin-and-mucosa condition. No punched-out tips and no strong odor.
- Leukemia-related gum changes. Swollen, spongy gums that bleed, often with easy bruising, tiredness, or frequent infections. People with low white counts can also develop necrotic gum ulcers, so we don't take these lightly.
- Canker sores on the gums. Round, single sores with a red ring. They're unusual on the gum right around the teeth and they don't eat away the gum tips. See canker sores.
- Gum abscess or pericoronitis. A localized, swollen, painful spot, often with pus, around one tooth or a partly erupted wisdom tooth. Learn about pericoronitis and tooth abscesses.
How long does trench mouth last? Does it go away on its own?
With treatment, most people feel a big difference within a day or two. The gray film clears and the gums settle over roughly 1 to 2 weeks. The gum tips that were lost may not grow all the way back, so some people are left with small dark triangles between the front teeth.
Without treatment, the pain can ease a bit after the acute phase, but the infection often smolders and flares again, destroying a little more gum and bone each time. That's how necrotizing gingivitis turns into necrotizing periodontitis. So, no, we don't recommend waiting it out.
Trench mouth treatment: what we do at the dentist
This is one of the gum infections we treat directly in the office, and it usually responds quickly. Necrotizing gingivitis treatment follows a fairly standard plan backed by periodontal guidelines:
- Confirm the diagnosis. We look at the pattern of the ulcers, ask about fever, stress, smoking, sleep, and health history, and make sure it isn't a herpes infection or something else.
- Gentle cleaning (debridement). With the area numbed, we carefully remove the gray film and the plaque and tartar around the teeth. We keep it gentle at the first visit because the tissue is so sore.
- Prescription antiseptic rinse. Usually chlorhexidine, sometimes with diluted hydrogen peroxide rinses in the first days.
- Antibiotics when they're needed. If you have a fever, swollen glands, feel unwell, or aren't improving with cleaning alone, we prescribe an antibiotic. Metronidazole is the usual first choice, with amoxicillin as an alternative. Antibiotics help but don't replace the cleaning.
- Pain control. Usually an over-the-counter pain reliever is enough once the cleaning is done.
- Close follow-up. We like to see you again within a few days, and we do more thorough cleaning as the gums calm down.
- Treat what's underneath. Once the acute infection is controlled, we treat the gingivitis or periodontitis that set the stage and give you a home care plan you can stick with.
- Look at the bigger picture. We talk about smoking, stress, and sleep, and, when it makes sense, we coordinate with your physician about bloodwork or an underlying condition. Patients with HIV, cancer treatment, transplants, or other medical complexity get extra coordination through our medically complex care approach.
If gum tissue has been badly damaged or bone has been lost, we may refer you to a periodontist (gum specialist) for further care.
Trench mouth is painful enough that many people call it an emergency, and we agree. If you think you have it, call us. Our emergency dental care page explains how to reach us quickly.
Trench mouth home care, step by step
Home care won't replace a dental cleaning, but it eases the pain while you're waiting to be seen and helps healing afterward.
- Keep brushing, gently. Use an extra-soft toothbrush and warm water. It hurts, but stopping lets plaque pile up and feeds the infection. After your cleaning, get back to your full routine as soon as you can.
- Rinse often. Warm salt water (½ teaspoon salt in a cup of water) several times a day. Once we've prescribed a chlorhexidine rinse, use it exactly as directed.
- Try a diluted peroxide rinse for the first few days if we recommend it. Use an oral rinse made for the purpose, or mix 3% drugstore hydrogen peroxide with an equal amount of water. Swish and spit. Don't swallow it.
- Control the pain. Acetaminophen or ibuprofen, as the label directs, unless your doctor has told you to avoid them.
- Stop smoking or vaping, at least for now. It slows healing and is one of the main reasons trench mouth comes back.
- Sleep, drink plenty of water, and eat real food. Soft, nutritious foods like eggs, yogurt, soups, smoothies, and pasta. Skip spicy, acidic, and crunchy foods and alcohol while the gums are raw.
- Finish any antibiotic exactly as prescribed, and avoid alcohol while taking metronidazole, as the label directs.
Our home care instructions cover brushing and flossing technique for once the soreness is gone.
Things that don't help
- Don't scrape off the gray film yourself. It bleeds, hurts, and spreads the raw area.
- Don't use leftover antibiotics. The wrong drug or dose can delay proper care, and antibiotics alone don't fix trench mouth.
- Don't swish with full-strength peroxide, rubbing alcohol, or bleach. These burn tissue that's already damaged.
- Don't just mask the breath. Mints and mouthwash cover the smell for a few minutes. The smell goes away when the infection does.
Over-the-counter options
These can make you more comfortable. None of them cure trench mouth on their own.
| Type | What it does | Things to know |
|---|---|---|
| Pain relievers (acetaminophen, ibuprofen) | Overall pain control | Follow the label. Use children's products and doses for kids. Ask your doctor first if you're pregnant; ibuprofen is generally avoided later in pregnancy. |
| Oxygenating rinses (hydrogen peroxide, about 1.5%) | Help loosen debris and clean ulcerated gums | Swish and spit. Use for a short time only, as the label directs. Adults should supervise children. |
| Alcohol-free antiseptic rinses (such as cetylpyridinium chloride) | Reduce plaque bacteria | Alcohol-free stings less. Prescription chlorhexidine is stronger if we've prescribed it. |
| Numbing gels (benzocaine, lidocaine) | Short relief before brushing or eating | Wears off fast. Do not use benzocaine in children under 2; the FDA warns of a rare but dangerous blood condition. |
| Extra-soft toothbrush | Lets you keep cleaning without tearing the gums | Replace it once you've healed. |
How to keep trench mouth from coming back
Trench mouth can recur, especially if the habits that set it up stay the same. The things that help most:
- Quit smoking. This is the biggest single change for most adults who've had it.
- Clean between your teeth daily with floss, interdental brushes, or a water flosser, and brush twice a day with a fluoride toothpaste.
- Keep up regular cleanings and dental exams so gingivitis gets handled before it can turn into something worse.
- Protect your sleep and eat regularly, especially during high-stress stretches.
- Keep medical conditions in check. If you have diabetes, good blood sugar control helps your gums too. See diabetes and your mouth.
- Call early if you feel the same sore, bleeding gums starting again. A quick cleaning at the first sign is much easier than treating a full flare.
Trench mouth in pregnancy, kids, and people with weakened immunity
Pregnancy
Swollen, bleeding gums are common in pregnancy, and most of the time it's pregnancy gingivitis, not trench mouth. If you do develop painful, cratered gums, dental cleaning is safe during pregnancy. We'll choose rinses and any medicines with your pregnancy in mind and check with your OB when needed.
Children
Trench mouth is uncommon in children in the U.S. Worldwide, it's mostly seen in children who are malnourished. A young child with sore, bleeding gums and a fever is far more likely to have a first herpes infection or hand, foot, and mouth disease. Either way, a child who won't eat or drink should be seen promptly.
People with HIV, cancer treatment, or other immune problems
Necrotizing gum disease is more common, and can move faster, when the immune system is weakened. If you're on chemotherapy or have a low white blood cell count, painful gum ulcers are a same-day call, both to us and to your oncology team. For patients going through head and neck cancer treatment, our head and neck cancer dental care page covers how we work alongside your oncology team. People living with HIV get the same respectful, straightforward care as anyone else. Prompt treatment matters more than anything.
When to see a dentist about trench mouth
Make an appointment if:
- Your gums are suddenly painful and bleeding, and the tips between your teeth look cratered or gray
- You have bad breath or a foul taste that started along with sore gums
- You've had trench mouth before and feel it starting again
- Sore gums haven't improved after a few days of gentle brushing and rinsing
Get care quickly (today) if:
- You have a fever, feel very unwell, or have swollen glands in your neck
- Your face, lip, or jaw is swelling, or you're having trouble swallowing or opening your mouth
- The ulcers are spreading to your cheeks, lips, or palate
- You're on chemotherapy, have a low white count, have had a transplant, or have advanced HIV
- You can't eat or drink enough because of the pain
Trench mouth FAQ
What is trench mouth?
Trench mouth is a fast-moving, painful gum infection in which the tips of gum between the teeth break down and die. It causes bleeding, a gray film over the gums, and strong bad breath. Its medical name is necrotizing gingivitis, and it used to be called acute necrotizing ulcerative gingivitis (ANUG) or Vincent's infection. It's uncommon and responds well to prompt dental treatment.
Is trench mouth contagious?
No, not in the usual sense. The bacteria involved are normally present in many healthy mouths, and trench mouth develops when a person's own defenses are lowered by things like stress, smoking, poor sleep, or an immune problem. You can't catch it from kissing or sharing a drink. It's still a good idea not to share toothbrushes while your gums are bleeding.
How do you get trench mouth?
Trench mouth usually develops when plaque has built up on already inflamed gums and something lowers your resistance at the same time. Common triggers are stress, smoking, lack of sleep, poor nutrition, and a recent illness. A weakened immune system from HIV, leukemia, chemotherapy, or immune-suppressing medicine raises the risk. Most people who get it have several of these factors at once.
What does trench mouth look like?
The gum tips between the teeth look "punched out" or cratered instead of pointed, and they're covered with a gray or yellow-white film. The gum edges are bright red and bleed easily. It often starts around the lower front teeth. Ordinary gingivitis, in contrast, makes the gum tips puffy and rounded rather than cratered.
How do you treat trench mouth?
A dentist gently cleans away the dead tissue, plaque, and tartar, usually with the area numbed, and prescribes an antiseptic rinse such as chlorhexidine. Antibiotics like metronidazole are added if you have a fever, swollen glands, or aren't improving. At home, keep brushing gently with a soft brush, rinse with warm salt water, take an over-the-counter pain reliever as directed, and stop smoking. Follow-up visits finish the cleaning once the gums calm down.
Can trench mouth be cured?
Yes. With professional cleaning, rinses, and antibiotics when needed, the infection clears, usually within 1 to 2 weeks. Gum tips that were destroyed may not grow back completely, which can leave small gaps between the teeth. Trench mouth can come back if the underlying habits or health issues aren't addressed.
Does trench mouth go away on its own?
Not reliably. The pain may ease for a while, but untreated trench mouth tends to smolder and flare again, destroying more gum and eventually bone with each episode. That can turn necrotizing gingivitis into necrotizing periodontitis, with permanent loss of tooth support. Seeing a dentist within a day or two is the safest course.
How long does trench mouth last?
With treatment, most people feel much better within one or two days, and the gums heal over about 1 to 2 weeks. Without treatment, it can drag on and keep coming back. If sore, bleeding gums aren't clearly improving within a few days of treatment, let your dentist know.
Why is it called trench mouth?
The name dates to World War I, when the infection was common among soldiers in the trenches. They were under constant stress, short on sleep and food, smoked heavily, and couldn't keep their teeth clean, which is a near-perfect setup for the disease. It's also called Vincent's infection, after the French doctor who described the bacteria involved in the late 1800s.
What is the difference between necrotizing gingivitis and necrotizing periodontitis?
Necrotizing gingivitis affects only the gum tissue, and the bone underneath is still intact. Necrotizing periodontitis means the infection has destroyed some of the attachment and bone that hold the teeth, which can't fully grow back. Periodontitis is more likely with significant immune problems or after repeated, untreated episodes. Both are treated with cleaning, rinses, and antibiotics when needed, followed by ongoing gum care.
Is trench mouth a sign of HIV or another immune problem?
Not necessarily. Most people who get trench mouth are healthy young adults dealing with stress, smoking, and too little sleep. Because necrotizing gum disease is linked to how well the immune system is working, a dentist may suggest bloodwork through your physician, including an HIV test, if it happens without a clear trigger or keeps coming back. Most of the time the results are normal.
Can trench mouth be dangerous?
For most people in the U.S., trench mouth is very treatable and doesn't cause lasting harm beyond some gum loss. Left untreated, it can damage the bone around the teeth and lead to loose teeth. In people with severe malnutrition or immune suppression, necrotizing infections can spread into the face, which is why fever, facial swelling, or spreading ulcers need care the same day.
Can trench mouth come back?
Yes. Trench mouth recurs more often in people who keep smoking, stay under heavy stress, or don't clean between their teeth. Each episode can cost a bit more gum and bone. Quitting smoking, daily flossing, regular cleanings, and calling your dentist at the first sign of a flare all lower the chance of it returning.
Sore, bleeding gums that came on fast?
If you're in the Jacksonville area and your gums suddenly hurt, bleed, and smell bad, call us. Trench mouth is one of the gum infections we treat right here in the office, and the sooner it's cleaned, the faster it settles down.
Related conditions
Sources
- Gasner NS, Brizuela M, Schure RS. Necrotizing Periodontal Diseases. StatPearls. National Library of Medicine; updated 2025.
- Herrera D, Retamal-Valdes B, Alonso B, Feres M. Acute periodontal lesions (periodontal abscesses and necrotizing periodontal diseases) and endo-periodontal lesions. J Periodontol. 2018;89(Suppl 1):S85–S102.
- Papapanou PN, Sanz M, et al. Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 2018;89(Suppl 1):S173–S182.
- Herrera D, Alonso B, de Arriba L, Santa Cruz I, Serrano C, Sanz M. Acute periodontal lesions. Periodontol 2000. 2014;65(1):149–177.
- Herrera D, Papapanou PN, Chapple I, et al. Management of acute periodontal conditions: the EFP S2k level clinical practice guideline. J Clin Periodontol. 2026.
- U.S. Food and Drug Administration. Risk of serious and potentially fatal blood disorder prompts FDA action on oral over-the-counter benzocaine products. 2018.
This page is for general education and isn't a diagnosis. Every mouth is different. If you have a sore you're worried about, see your dentist or physician. Photos marked Wikimedia Commons are used under their listed licenses and may have been cropped or resized.