If you’ve ever experienced a tingling at the back of your jaw when eating something sweet or sour, you’re not alone. It’s actually very common.

What you’re feeling is your salivary glands doing their job: producing saliva. However, certain foods — or even just the thought of certain foods — can cause these glands to go into overdrive.

To understand why your salivary glands respond this way, you first need to understand what saliva does.

The Role of Saliva

Saliva is 99.5 percent water, but it also contains certain substances that help you chew, taste and swallow, as well as protect your teeth.

Your body makes 2 to 4 pints of saliva every day, and most of it is produced in the late afternoon. However, your taste buds play an important role in how much saliva you make.

Spicy foods, sweet foods and acidic, sour-tasting foods can trigger your salivary glands — which are located beneath your tongue, under your jaw and below your ears — to produce more saliva. And sometimes you can feel the glands at work, especially the large parotid glands situated between your jaw and ears.

“When starting to eat or sometimes even thinking about eating (e.g. thinking of biting a lemon) these glands produce saliva to make digesting food easier,” said Dr. Richard Pladdet. “Some people feel the glands at that point produce saliva.”

Food That Affects Your Senses

This is often described as a tingling and sometimes slightly painful sensation, but it’s typically nothing to worry about. You’re simply experiencing a bit of sensory overload, and your salivary glands are trying to quickly produce enough saliva to help you digest the food you’re chewing.

However, if what you’re experiencing is very painful, or if you notice swelling or inflammation in the areas where salivary glands are located, you should see a doctor. Sometimes your glands can become blocked or infected, or there could be another disorder causing the pain, such as Frey’s Syndrome, a rare disorder that includes facial flushing and even sweating while eating.