Nutrition basics
Learning Center
Canker sore
Canker sore — Learn about the causes, treatment and prevention of this painful mouth sore.
Caffeine: Is it dehydrating or not?
Caffeinated drinks usually won't dehydrate you, but water is still your best option.
Caffeine: How much is too much?
Is your caffeine habit causing problems? Find out how much is too much and if you need to curb your consumption.
COVID-19: Long-term effects
Learn about the possible long-term effects of COVID-19.
Bronchitis
Bronchitis is an inflammation of the tubes that carry air to and from the lungs. Coughing and shortness of breath are the major symptoms.
Bone metastasis
Learn about the symptoms and causes of cancer that spreads to the bones. Find out about treatments, including medications, radiation and surgery.
Bone health: Tips to keep your bones healthy
Find out what you can do to promote and protect bone health.
Bone and joint problems associated with diabetes
If you have diabetes, you're at increased risk of various bone and joint disorders.
Blood in semen
Finding blood in your semen can be alarming, but the cause is usually benign. Find out possible causes and when to see a doctor.
Blepharitis
This often chronic eyelid condition can be difficult to treat. It might be uncomfortable, but it doesn't usually damage eyesight and isn't contagious.