The last time you visited your doctor for an illness, he or she might have ordered a CBC test to help determine the diagnosis. CBC stands for complete blood count, but what does that mean? And what do all those numbers on the result sheet mean? Find out by taking this quiz.

Gazing down on the spectacular view from a mountaintop can take your breath away. That breathlessness is oftentimes more than just an awestruck reaction to the sights. It can be a symptom of altitude sickness, an illness that can strike hikers, mountain climbers, skiers and anyone who hits the 8,000-foot mark on a mountain.

Lymphomas are a type of cancer that affects the lymphatic system. Learn more about non-Hodgkin lymphoma (NHL) by taking this true-false quiz.

More than a million Americans are infected with HIV, the virus that causes AIDS. Find out more about HIV and AIDS by taking this quiz.

Viral hepatitis comes in several forms, and all of them can make you very sick. Some forms of the virus can be eliminated from the body, but other forms remain for a lifetime. Take this quiz to test your knowledge of hepatitis.

Learn more about impotence by taking this multiple-choice quiz.

One variant of this illness is known as "mad cow disease." To help make sense of this puzzling disease, take this quiz.

Some men cope with their inevitable loss of hair by wearing a cap most of the time. Some don an artificial hairpiece to cover their loss. Still others shave their whole head. There's more to know about baldness than toupees, though. Learn more by taking this quiz.

The human appendix is a 3- to 6-inch narrow tube located where the small and large intestines join. It's mostly known for becoming inflamed, affecting thousands of Americans each year. To learn more about the appendix, take this quiz.

Anthrax is a serious disease that can affect the skin, lungs, and digestive tract. Learn more about this disease by taking this quiz.