A cut or crack at the corner of your mouth is almost always a condition called angular cheilitis, and it heals within about two weeks once you address what’s causing it. The key is keeping the area dry, protected from saliva, and treated for any underlying infection. Here’s how to get there.
Why the Corner of Your Mouth Keeps Cracking
These splits happen when moisture, usually saliva, pools in the creased skin at the corners of your mouth. The constant dampness softens and breaks down the skin (a process called maceration), creating tiny fissures. Once the skin is broken, fungi and bacteria that naturally live on your skin can move in and turn a small crack into a stubborn, painful sore.
Several things make this more likely to happen. Licking your lips is the most common trigger, since it deposits saliva right into the crease. Ill-fitting dentures can change the way your lips sit and create deeper folds where moisture collects. Wearing a face mask for long periods traps humidity around your mouth. Drooling during sleep does the same thing. Braces or other orthodontic appliances can also redirect saliva toward the corners.
Nutritional deficiencies account for about 25% of all angular cheilitis cases. Iron deficiency is the most common culprit, followed by deficiencies in B vitamins, specifically riboflavin (B2), niacin (B3), B6, and B12. These nutrients play direct roles in skin repair and maintaining the tissue lining your mouth, so running low on them makes the corners of your lips more vulnerable to cracking and slower to heal.
How to Treat It at Home
The most important step is creating a physical barrier between your skin and saliva. Apply a thick layer of petroleum jelly (Vaseline) or a similar ointment like Aquaphor to the corners of your mouth, especially before bed and first thing in the morning. The petroleum-based ointment soothes the broken skin and blocks saliva from re-soaking the area, which is what keeps the cycle going.
If the crack looks red, swollen, or crusty, there’s likely a fungal or bacterial infection involved. An over-the-counter antifungal cream containing clotrimazole, terbinafine, or miconazole can help clear it. Apply a thin layer to the affected corner twice a day, then seal over it with your petroleum jelly barrier. Many cases involve both fungal and bacterial organisms at the same time, which is why stubborn sores sometimes need a combination approach.
Two natural options with some antimicrobial support: coconut oil has antifungal and antibacterial properties and can soothe irritation when applied as a thin layer. Honey also has antimicrobial and wound-healing properties. Either can work as a supplement to your main treatment, though neither is as reliable as an antifungal cream for an active infection.
Break the Habits That Slow Healing
Stop licking your lips. This is harder than it sounds because the cracked skin feels dry, and licking provides instant (but very temporary) relief. Each time you lick, you’re reintroducing the moisture and digestive enzymes in saliva that caused the problem. When you feel the urge, apply your barrier ointment instead.
Avoid opening your mouth wider than necessary while the crack heals. Eating large bites, yawning broadly, or stretching your mouth during dental work can re-tear the fissure just as it’s starting to close. Cut food into smaller pieces, favor softer meals, and be conscious of how wide you’re opening when you talk. Acidic and salty foods, like citrus or chips, will sting the open crack and can irritate the surrounding skin.
When Over-the-Counter Care Isn’t Enough
If the crack hasn’t improved after a week of consistent home treatment, or if it’s getting worse with increasing redness, swelling, pus, or spreading soreness, it’s time for a stronger approach. A healthcare provider can prescribe a targeted combination: a protocol used at some medical centers mixes 2% clotrimazole cream with 2% mupirocin cream in equal parts, applied to the corners of the mouth morning and night. This covers both fungal and bacterial infections simultaneously. With proper treatment, the condition typically clears within about two weeks.
If your angular cheilitis keeps coming back, your provider may want to check for nutritional deficiencies with a blood test, particularly iron and B vitamin levels. Recurring cracks can also signal an immune system issue, poorly fitting dentures, or chronic dry mouth that needs its own treatment.
Preventing It From Coming Back
Once you’ve healed, a nightly application of petroleum jelly to the corners of your mouth is the simplest prevention strategy, especially in dry or cold weather. If you wear dentures, make sure they fit properly. Dentures that have become loose due to age-related bone loss create deeper skin folds at the mouth corners, which trap more moisture. A dentist can reline or replace them.
Pay attention to your diet. Getting enough iron (from red meat, beans, spinach, or fortified cereals) and B vitamins (from eggs, dairy, whole grains, and leafy greens) supports the skin’s ability to repair itself and resist breakdown. If you suspect a deficiency, a simple blood panel can confirm it, and supplementation can make a noticeable difference in how quickly and frequently your lips crack.
Stay hydrated through drinking water rather than constantly wetting your lips. Use a humidifier in dry indoor environments, particularly during winter. And if you notice the earliest sign of cracking, a slight tightness or redness at the corner, start your barrier ointment immediately rather than waiting for a full split to develop.