Ah, canker sores. These tiny, painful bumps are a nuisance at best and totally debilitating at worst. A nasty enough canker sore in a particularly inconvenient place can leave you eating nothing but mashed potatoes and milkshakes for a week. While that sounds pretty delicious in theory, the pain of the canker sore definitely is not! So, what makes these tricky sores appear, and how do we rid ourselves of them for good? We did our research.

A canker sore is essentially just an ulcer in your mouth. Typically, they’re small, whitish bumps with an inflamed red border. They can be caused by bacteria, a cut inside of the mouth, or elevated levels of stress. Often, they’ll appear when the immune system is already compromised, so if you notice them pop up while you’ve got the sniffles, you know why.

Preventing canker sores is sometimes difficult, as they are unpredictable and, to a certain degree, inevitable. However, if you’re someone who finds yourself getting canker sores a lot, it helps to note when you’re seeing them. After eating certain foods? During times of extreme stress at work? While you’re already feverish? By identifying what factors tend to make you susceptible to sores, you can take active steps to try to avoid them.

If you are suffering from a canker sore, there are several topical gels available on the market to numb the pain and speed healing. A canker sore shouldn’t last more than a week or two, so if it feels like it’s been hanging around longer than that, consult your dentist or doctor.