As a source of foodborne illness, E. coli bacteria can be deadly. But aren't E. coli also regular residents of our intestines? When do E. coli become the "bad guys"? To learn more about this common bacterium, take this quiz.

Many of us turn to dieting to shed a few extra pounds, but for some people, dieting becomes an obsession that turns into an eating disorder. This quiz provides helpful information on eating disorders.

Ear, nose, and throat problems affect both children and adults. Knowing how to prevent them and how to treat them if they occur can help you stay healthy. See what you know about the ears, nose, and throat by taking this true-false quiz.

Infections of the middle ear, called otitis media, seem to be a common badge of childhood. Seventy-five percent of children experience at least one episode of otitis media by their birthday. How much do you know about this illness?

Marijuana contains the flowers, stems, seeds, and leaves of the hemp plant. To learn more about marijuana, take this quiz.

Substance-use disorder is also called drug addiction. It can break apart families, ruin personal relationships, and make it difficult to keep a job.

What happens to that cheeseburger and fries you had for lunch? During the digestive process, food is converted into energy that's used by your body. Take this quiz to see how much you know about how digestion works.

At any given time, millions of people in the U.S. are trying to lose weight. They spend billions of dollars each year on weight-loss products and services. Learn more about diets and weight loss by taking this quiz.

Anyone can get diarrhea. In fact, the typical American adult experiences diarrhea about 4 times a year. Most cases of diarrhea last a day or 2 and need no treatment. Find out more about this common digestive problem by taking this quiz.

The kidney's main job is to get rid of excess fluid and waste material in your blood. A person with kidney failure needs dialysis or a kidney transplant to survive. Learn more about dialysis by taking this quiz.