It happens every day: You’re out for a run or motorboating on the lake and, whoosh, an insect lands in your mouth. The ick factor is high, but can it cause any real harm? One expert, Bobbi Pritt, a microbiologist, pathologist and director of the Clinical Parasitology Laboratory at the Mayo Clinic in Rochester, Minn., unearths when swallowing an insect is harmless, which ones can be dangerous and why you should cook your bugs first.

Summertime blues

Most people get bit or stung during the summer months by something, and many of us even eat a few critters. “I used to Rollerblade a lot, and I know that I’ve swallowed my fair share of insects,” Dr. Pritt says. “It’s gross, but it’s just a fact of life.”

For the most part, eating a bug isn’t cause for worry, she says. In general, your body will digest arthropods, which include arachnids like spiders, mites and ticks, and insects such as gnats, flies, mosquitoes, fleas and bedbugs, “just like any other food,” she says. “Eating a bug now and then probably won’t be a problem for most.”

When to worry

Certain bugs can be a problem if you swallow them, including insects that can sting or bite such as bees, wasps, fire ants and some types of caterpillars, says Dr. Pritt. “Usually eating one will just cause mild pain and localized swelling if it bites or stings you,” she says. But for people who are allergic, eating one that then stings you can lead to breaking out in hives; swelling of the face, throat or mouth; difficulty breathing; dizziness; a drop in blood pressure; and even cardiac arrest. “If they don’t have an EpiPen, eating a bug they’re allergic to can be fatal,” she says.

Click for more from The Wall Street Journal.