Red, painful gums are almost always a sign of inflammation, and the most common cause is the buildup of bacterial plaque along your gumline. About 42% of U.S. adults over 30 have some form of gum disease, so if your gums look red and feel sore, you’re far from alone. The good news is that the earliest stage is reversible with the right care, but it helps to understand what’s actually happening and whether something beyond plaque might be driving it.
How Plaque Triggers Gum Inflammation
Your mouth naturally contains bacteria that form a sticky film (plaque) on your teeth throughout the day. When plaque sits along the gumline for too long, those bacteria release substances that your immune system recognizes as a threat. Your body responds by flooding the area with immune cells, which causes the blood vessels in your gum tissue to widen and become more permeable. That’s what creates the redness, swelling, and tenderness you’re noticing.
If plaque isn’t removed, it hardens into tarite (calculus), which you can’t brush away at home. Tartar traps even more bacteria against the gums and keeps the inflammatory cycle going. The longer this continues, the more damage accumulates.
Gingivitis vs. Periodontitis
Gum disease has two main stages, and telling them apart matters because one is reversible and the other isn’t.
Gingivitis is the early stage. Your gums are red, puffy, and may bleed when you brush or floss. It doesn’t always cause pain, which is why some people miss it. At this point, only the soft gum tissue is affected, and no permanent damage has occurred. With improved oral hygiene and a professional cleaning, gingivitis typically resolves completely.
Periodontitis is what happens when gingivitis goes untreated. The gums start pulling away from the teeth, forming deeper pockets that trap bacteria. Over time, the infection breaks down the bone and connective tissue holding your teeth in place. Teeth can loosen and eventually fall out. Nearly 60% of adults over 65 have periodontitis, making it one of the leading causes of tooth loss in older adults. Non-surgical treatment (deep cleaning below the gumline) has success rates around 80 to 90% for controlling the disease and preventing further progression, but bone that’s already lost doesn’t grow back on its own.
Other Reasons Your Gums May Hurt
Plaque-driven gum disease is the most likely explanation, but it’s not the only one. Several other factors can make gums red and painful.
Hormonal Changes
Pregnancy, puberty, menstruation, and menopause all cause shifts in hormone levels that change how your immune system responds to the bacteria already in your mouth. During pregnancy, for example, the body ramps up production of inflammatory signaling molecules, which means even a normal amount of plaque can trigger a much stronger gum reaction. This is common enough that it has its own name: pregnancy gingivitis.
Vitamin C Deficiency
A severe lack of vitamin C over at least three months can lead to scurvy, which causes swollen, bleeding gums that may turn purple and spongy. True scurvy is rare in developed countries, but people with very limited diets, certain digestive conditions, or heavy alcohol use are at higher risk. A blood test can confirm your vitamin C levels.
Autoimmune and Skin Conditions
Sometimes red, painful gums aren’t caused by bacteria at all. A condition called desquamative gingivitis causes the outer layer of gum tissue to peel away, leaving raw, sore patches. In about 90% of these cases, the underlying cause is one of three conditions: erosive lichen planus (an immune-driven skin disorder), mucous membrane pemphigoid, or pemphigus vulgaris. These require a biopsy to diagnose and a different treatment approach than standard gum disease.
Abscess
If your gum pain is intense and localized to one spot, you may have an abscess, which is a pocket of infection. Signs include a visible swelling or bump on the gum, a bad taste in your mouth, and sometimes fever. If you develop facial swelling, fever, or difficulty breathing or swallowing, that suggests the infection is spreading and you need emergency care.
What You Can Do at Home
If your symptoms are mild (general redness, slight tenderness, some bleeding when flossing), improving your daily routine can make a significant difference. The American Dental Association recommends brushing twice a day and cleaning between your teeth once a day with floss, interdental brushes, or a water flosser. These tools remove plaque and trapped food before they can harden into tartar.
Use a soft-bristled toothbrush and brush for a full two minutes. Hard bristles and aggressive scrubbing can actually irritate inflamed gums further. If your gums bleed when you floss, that’s not a reason to stop. It’s a sign of inflammation that typically improves within a week or two of consistent flossing as the gum tissue heals.
Rinsing with warm salt water can temporarily soothe sore gums. For more persistent inflammation, your dentist may prescribe a medicated mouth rinse to help bring the bacterial load under control.
What Happens at the Dentist
A dental professional can determine whether you have gingivitis, periodontitis, or something else entirely. The exam involves measuring the depth of the pockets between your gums and teeth with a small probe. Healthy pockets are typically 1 to 3 millimeters deep. Deeper pockets suggest periodontitis.
For gingivitis, a professional cleaning to remove plaque and tartar is usually all that’s needed. For periodontitis, the standard treatment is a deep cleaning called scaling and root planing, where the dentist or hygienist cleans below the gumline and smooths the root surfaces so gums can reattach more easily. This is done under local anesthesia and may take two or more visits depending on severity. Most people notice a significant reduction in redness and soreness within a few weeks.
Risk Factors Worth Knowing
Some people are more prone to red, painful gums than others, even with decent brushing habits. Smoking is one of the strongest risk factors for gum disease because it reduces blood flow to the gums and weakens the immune response. Diabetes makes gum infections harder to fight and slower to heal. Certain medications, particularly those that cause dry mouth, remove one of your body’s natural defenses against bacterial buildup. And genetics play a role: some people simply mount a stronger inflammatory response to plaque than others.
If you notice your gums are consistently red and sore despite good brushing and flossing, or if you see your gums pulling away from your teeth, pus between your teeth, loose teeth, or persistent bad breath, those are signs the problem has moved beyond what home care alone can fix.