4. Ear Infection A viral or bacterial infection in the middle ear can develop when the ear's Eustachian tube becomes blocked and filled with fluid. Ear infections are most common among children.

Remember the “good” bacteria mentioned earlier? Douches, like soaps, can irritate and kill off that good bacteria, leaving your vagina more vulnerable to infection.

Here's where to buy the best affordable jewelry. Our style editors tested top brands to see which are tarnish-proof, hypoallergenic, and high quality.

Find the best earbuds at every price point, all tested and approved by Mashable audio experts. Check out the top buds from Bose, Sony, and Apple.