Cracked corners of the mouth, known medically as angular cheilitis, usually heal with one simple first step: applying a barrier ointment like petroleum jelly to keep the area dry and protected. Most cases are caused by saliva pooling in the skin folds at the corners of your lips, which leads to irritation, cracking, and sometimes a fungal or bacterial infection. Treatment depends on whether the cracks are just dry and irritated or have become infected.
Why the Corners of Your Mouth Crack
The root cause is almost always moisture. Saliva collects in the small creases at the corners of your mouth, and over time that constant dampness breaks down the skin. The damaged skin dries out, cracks, and becomes an easy entry point for yeast (most commonly Candida) or bacteria. Once an infection sets in, the cracking gets worse and healing stalls.
Several things make saliva buildup more likely:
- Lip licking. A habit that feels soothing but constantly reintroduces moisture and digestive enzymes to the area.
- Ill-fitting dentures. When dentures don’t restore the full height of the lower face, skin folds form at the mouth corners and trap saliva. Research in oral pathology has linked loss of vertical bite height directly to angular cheilitis in denture wearers.
- Nutritional deficiencies. Low levels of iron, B vitamins (especially B2 and B12), or zinc can make the skin at the lip corners thinner and more vulnerable to breakdown.
- Oral thrush. A yeast infection inside the mouth can spread to the corners and trigger or worsen cracking.
- Diabetes and immune suppression. Both increase susceptibility to fungal overgrowth in moist skin folds.
Start With a Barrier Ointment
For most people, the cracking is driven by irritation rather than infection. Protecting the corners of your mouth with a thick barrier ointment is often enough to resolve it. Petroleum jelly is the most recommended option. Zinc oxide paste and plain lip balm also work. The goal is to create a physical shield that prevents saliva from sitting on the skin.
Apply a generous layer to both corners of your mouth before bed and reapply throughout the day, especially after eating or drinking. This single step resolves many mild cases within a week or two. If you notice improvement but the cracks keep returning, you’re likely dealing with an ongoing moisture problem (lip licking, drooling during sleep, or a dental fit issue) that needs to be addressed at its source.
When You Need Antifungal or Antibiotic Treatment
If the cracks are red, swollen, crusty, or oozing, an infection has likely developed. Fungal infections are the most common culprit. Over-the-counter antifungal creams containing clotrimazole or miconazole, applied to the corners two to three times daily, clear most fungal cases. Your doctor or dentist may prescribe a stronger antifungal if over-the-counter options don’t work.
Bacterial infections look slightly different. They tend to produce a yellowish crust or honey-colored discharge. These require a topical antibiotic, which you’ll need a prescription for. In some cases, both fungal and bacterial organisms are present, and treatment covers both.
A topical steroid cream is sometimes used alongside antifungal or antibiotic treatment to reduce swelling and pain, but steroids alone can actually make a fungal infection worse. Don’t apply hydrocortisone to cracked mouth corners without knowing what’s causing the problem.
How It Differs From a Cold Sore
Cold sores and angular cheilitis can look similar at first glance, but they behave differently. Cold sores are caused by the herpes simplex virus and typically appear as clusters of small, fluid-filled blisters on or near the lips. They tingle or burn before the blisters appear, then crust over and heal in about 7 to 10 days.
Angular cheilitis stays specifically at the corners of the mouth, doesn’t form blisters, and tends to look more like raw, cracked skin or shallow splits. It also won’t resolve on its own the way a cold sore does. If you’re unsure which you’re dealing with, the location is the best clue: angular cheilitis is symmetrical and confined to the commissures (the exact corner where your upper and lower lips meet), while cold sores can appear anywhere along the lip line.
Check for Nutritional Gaps
Recurring cracks at the mouth corners, especially if they don’t respond well to barrier creams and antifungals, can signal a nutritional deficiency. Iron deficiency is the most common link, followed by deficiencies in riboflavin (vitamin B2), vitamin B12, folate, and zinc. These nutrients all play roles in maintaining the skin and mucous membranes around the mouth.
If your diet is low in red meat, leafy greens, eggs, legumes, or fortified grains, that’s worth addressing. A simple blood test can confirm whether a deficiency is contributing. Correcting the deficiency often stops the cycle of recurrence that topical treatments alone can’t break.
Preventing It From Coming Back
Angular cheilitis is frustrating because it recurs easily. The skin at the mouth corners is thin, and once it’s been damaged, it’s more prone to cracking again. A few habits make a real difference in prevention:
Stop licking your lips. This is the single most impactful change for people with recurring episodes. Saliva evaporates quickly, leaving the skin drier than before, and the cycle repeats. Use lip balm instead whenever you feel the urge to lick. Stay well hydrated so your lips feel less dry in the first place. Practice good oral hygiene to keep yeast levels in check inside your mouth.
If you wear dentures, have their fit evaluated. Loss of bite height is a well-documented cause of angular cheilitis in denture wearers because it creates deeper skin folds at the corners of the mouth where saliva pools. Adjusting or replacing dentures to restore proper facial height can eliminate the problem entirely. For people with diabetes or compromised immune systems, applying a thin layer of petroleum jelly or an antifungal cream to the mouth corners daily can help prevent flare-ups before they start.
How Long Healing Takes
Mild cases that are just dry and cracked typically improve within one to two weeks of consistent barrier ointment use. Infected cases treated with the right antifungal or antibiotic usually start improving within a few days, with full healing in two to three weeks. If you’ve been treating the area for more than two weeks with no improvement, the underlying cause may be something that needs further investigation, such as a nutritional deficiency, an immune issue, or an allergic reaction to a product you’re using on or near your lips.
During healing, avoid opening your mouth wide (for large bites of food or yawning), as this stretches and re-tears the fragile new skin forming at the corners. Eating softer foods and cutting things into smaller pieces helps the splits close without being repeatedly reopened.