Acid reflux occurs when stomach acid flows back up into the esophagus (the tube connecting your mouth and stomach), causing a burning sensation in the chest or throat known as heartburn. When acid ref . . .
Anemia is a condition in which you lack enough healthy red blood cells to carry adequate oxygen to your body's tissues. Having anemia can make you feel tired and weak. There are many forms of anemia, . . .
Anxiety is your body's natural response to stress. It's a feeling of fear or apprehension about what's to come. Anxiety disorders are the most common mental health conditions. They include generalized . . .
Arthritis is inflammation of one or more joints, causing pain and stiffness that can worsen with age. The most common types are osteoarthritis and rheumatoid arthritis. Osteoarthritis involves wear-an . . .
Asthma is a condition in which your airways narrow and swell and may produce extra mucus. This can make breathing difficult and trigger coughing, a whistling sound (wheezing) when you breathe out and . . .
The common cold is a viral infection of your nose and throat (upper respiratory tract). It's usually harmless, although it might not feel that way. Many types of viruses can cause a common cold. Child . . .
Chronic constipation is infrequent bowel movements or difficult passage of stools that persists for several weeks or longer. Constipation is generally described as having fewer than three bowel moveme . . .
Dengue (DENG-gey) fever is a mosquito-borne disease that occurs in tropical and subtropical areas of the world. Mild dengue fever causes a high fever, rash, and muscle and joint pain. A severe form of . . .
Depression is a mood disorder that causes a persistent feeling of sadness and loss of interest. Also called major depressive disorder or clinical depression, it affects how you feel, think and behave . . .
Diabetes is a condition that reduces a person's ability to use insulin to process glucose in the blood. The condition takes different forms, and each type produces varying symptoms. Some types may not . . .
Diarrhea is loose, watery stools (bowel movements). You have diarrhea if you have loose stools three or more times in one day. Acute diarrhea is diarrhea that lasts a short time and is common. It usua . . .
Influenza, or flu, is a respiratory illness caused by a virus. Flu is highly contagious and is normally spread by the coughs and sneezes of an infected person. You can also catch flu by touching an in . . .
Gastritis is a general term for a group of conditions with one thing in common: inflammation of the lining of the stomach. The inflammation of gastritis is most often the result of infection with the . . .
A headache is pain in the head or upper neck. They may be primary (not associated with a medical condition) or secondary (caused by an injury or medical condition). Primary headaches include tension, . . .
Heart disease describes a range of conditions that affect your heart. Diseases under the heart disease umbrella include blood vessel diseases, such as coronary artery disease; heart rhythm problems (a . . .
High blood pressure, or hypertension, occurs when your blood pressure increases to unhealthy levels. Your blood pressure measurement takes into account how much blood is passing through your blood ves . . .
High cholesterol means you have too much of a fatty substance called cholesterol in your blood. It's mainly caused by eating fatty food, not exercising enough, being overweight, smoking and drinking a . . .
Insomnia is a common sleep disorder that can make it hard to fall asleep, hard to stay asleep, or cause you to wake up too early and not be able to get back to sleep. Insomnia can sap not only your en . . .
Painful swallowing is relatively common. People of all ages may experience it. This symptom has many possible causes. Difficulty swallowing along with pain is generally a symptom of an infection or an . . .
Kidney stones (also called renal calculi, nephrolithiasis or urolithiasis) are hard deposits made of minerals and salts that form inside your kidneys. Diet, excess body weight, some medical conditions . . .
Menstrual cramps (dysmenorrhea) are throbbing or cramping pains in the lower abdomen. Many women have menstrual cramps just before and during their menstrual periods. For some women, the discomfort is . . .
Nausea is an unpleasant, diffuse sensation of unease and discomfort, often perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged. Nausea has many causes inclu . . .
Osteoporosis causes bones to become weak and brittle — so brittle that a fall or even mild stresses such as bending over or coughing can cause a fracture. Osteoporosis-related fractures most commonly . . .
A runny nose is never any fun, especially when it comes with a cold or allergies. It can interrupt your daily life, making you reach for the tissue box every few minutes. But what is a runny nose exac . . .
A sore throat is pain, scratchiness or irritation of the throat that often worsens when you swallow. The most common cause of a sore throat (pharyngitis) is a viral infection, such as a cold or the fl . . .
Stress is your body’s way of responding to any kind of demand or threat. When you sense danger—whether it’s real or imagined—the body's defenses kick into high gear in a rapid, automatic process known . . .
Type 2 diabetes is a chronic condition that affects the way your body metabolizes sugar (glucose). With type 2 diabetes, your body either doesn't produce enough insulin, or it resists insulin. Type 2 . . .
A urinary tract infection (UTI) is an infection in any part of your urinary system — your kidneys, ureters, bladder and urethra. Most infections involve the lower urinary tract — the bladder and the u . . .
Most people have a body temperature of about 98.6°F (37°C). Anything a degree above this is considered a fever. Fevers are often a sign that your body is fighting off some type of bacterial or viral i . . .