In-depth

Addison's disease

Addison's disease occurs when your adrenal glands produce insufficient amounts of certain important hormones. Treatment may include taking corticosteroids.

Agoraphobia

Do you feel trapped in your own home? Do you worry about having a panic attack? Find out how agoraphobia can be treated.

Amyloidosis

Amyloidosis causes an abnormal protein buildup in various organs, which can include your heart and kidneys, and can permanently damage them and disrupt their functions.

Anaphylaxis

Anaphylaxis is the most serious type of allergic reaction. It often occurs rapidly after exposure to an allergen and may be life-threatening.

Antibiotic-associated diarrhea

Antibiotics save lives, but they can also have side effects. The most common are mild to severe diarrhea and a serious type of colitis.

Appendicitis

Appendicitis occurs when the appendix becomes inflamed and filled with pus, creating potentially serious complications if not promptly treated.

Ascariasis

Ascariasis is a common type of roundworm infection found worldwide. It's spread by poor hygiene and improper sanitation. Infections are effectively treated with medication.

Bee stings

Bee stings — Comprehensive overview covers prevention, treatment of bee stings.

Behcet's disease

Behcet's disease affects several body systems and causes a variety of signs and symptoms. Find out what it is and how it's treated.

Bird flu (avian influenza)

A type of influenza normally found in birds, bird flu first appeared in humans in 1997. Experts worry it could lead to a flu pandemic.

Blastocystis hominis infection

A microscopic parasite causes Blastocystis hominis infection. Experts disagree as to whether this infection causes diarrhea and other associated signs and symptoms.

Blind loop syndrome

Blind loop syndrome occurs when a portion of bowel is bypassed. The condition is most often a complication of abdominal surgery.

C. difficile

C. difficile can be a life-threatening infection. It typically develops when antibiotics destroy other bacteria in your intestines, allowing C. difficile to flourish.

Carcinoid syndrome

Carcinoid tumors sometimes secrete chemicals that cause the signs and symptoms of carcinoid syndrome. Carcinoid tumors are rare. Carcinoid syndrome is even rarer.

Carcinoid tumors

Carcinoid tumors are rare, slow-growing cancerous tumors that most often occur in the gastrointestinal tract or in the lungs.

Celiac disease

Celiac disease is an immune reaction to gluten, a protein found in certain foods. As a result, the body is unable to absorb some important nutrients.

Cholera

Cholera causes severe diarrhea and can kill in a matter of hours, yet can be easily treated with oral or intravenous fluids.

Churg-Strauss syndrome

Churg-Strauss syndrome is a rare disorder marked by blood vessel inflammation that affects organs throughout the body. Asthma is the most common sign.

Colon cancer

Colon cancer and rectal cancer combined are the second-leading cause of cancer-related deaths in the United States. Regular screening tests can help reduce your risk.

Colon polyps

Colon polyps — small clumps of cells on your colon lining — are usually harmless, but some may become cancerous over time.

Crohn's disease

Crohn's disease is a form of inflammatory bowel disease (IBD) — a serious inflammation of the digestive tract that can cause abdominal pain and diarrhea.

Cryptosporidium infection

Cryptosporidium infection may cause diarrhea in healthy people, but for people with HIV/AIDS and weakened immune systems, the illness can cause serious complications.

Cyclic vomiting syndrome

Cyclic vomiting syndrome can last for hours or days and shares many triggers with migraines.

Cyclospora infection

Cyclospora infection is an uncommon foodborne intestinal infection that causes diarrhea. Outbreaks have been linked to contaminated water and produce.

Diabetes insipidus

Diabetes insipidus is a rare condition characterized by intense thirst and the excretion of large amounts of urine.

Diabetic neuropathy

Diabetes can damage nerves throughout your body — a condition known as diabetic neuropathy. Nerve damage can cause pain, disability and other serious complications.

Diverticulitis

Having bulging pouches (diverticulosis) in your digestive tract isn't necessarily a concern. But infected pouches (diverticulitis) can be a serious problem.

Drug allergy

Drug allergy can occur with many medications. Find out what you can do to recognize and avoid potentially dangerous reactions.

E. coli

E. coli bacteria normally live harmoniously in your gut. But when you eat food contaminated with a nasty strain of E. coli, serious illness may follow.

Ear infection (middle ear)

Ear infections are common in children. These bacterial or viral infections of the middle ear can cause mild to severe ear pain.

Ebola virus and Marburg virus

Ebola virus and Marburg viruses cause hemorrhagic fevers, serious and potentially life-threatening illnesses.

Ehrlichiosis

Ehrlichiosis is a tick-borne disease that causes flu-like symptoms. When you're outdoors, be aware of steps to prevent tick bites.

Endometriosis

Endometriosis is a common and often painful disorder in which tissue that normally lines the inside of your uterus grows outside your uterus.

Fecal incontinence

If you have difficulty controlling your bowel movements, don't shy away from talking to your doctor — effective treatments for fecal incontinence are available.

Food poisoning

Food poisoning has many forms, and some can be serious. Here's how to recognize food poisoning and ways to prevent getting sick.

Giardiasis

Giardia infection is a common waterborne illness. Learn the symptoms and reduce your risk.

Hantavirus pulmonary syndrome

Hantavirus pulmonary syndrome is initiated by a rodent-carried virus that infects the lung tissues, bringing on flu-like symptoms, respiratory problems and even death.

Hirschsprung's disease

Hirschsprung's disease, a disease of the colon, is present at birth and can cause serious problems passing stool.

HIV/AIDS

More than 39 million people are living with HIV — the virus that causes AIDS. Millions more are likely to become infected in the next decade.

Hunter syndrome

Hunter syndrome, a rare metabolic disorder, occurs when the body can't break down certain complex sugars. Complications occur as these sugars accumulate in the body.

Inflammatory bowel disease (IBD)

Inflammatory bowel disease can be painful and debilitating, and it can cause life-threatening complications. Find out more about treating this digestive system disorder.

Intestinal ischemia

Intestinal ischemia occurs when the blood supply to your digestive system is reduced. Abdominal pain is a common symptom. Several treatment options are available.

Intestinal obstruction

Intestinal obstruction — a serious condition that requires prompt medical attention — occurs when a blockage of the intestine prevents food or fluid from passing through.

Intussusception

A rare but serious disorder, intussusception occurs when one part of the intestine slides into an adjacent part, often causing intestinal obstruction.

Ischemic colitis

Ischemic colitis is a disorder in which the colon becomes inflamed, usually due to a disruption of blood flow.

Jet lag disorder

Flying across multiple time zones disrupts your natural body rhythms, leading to sleep problems and other symptoms. Learn how to put jet lag to rest.

Kawasaki disease

Kawasaki disease — the leading cause of acquired coronary disease in children — causes artery wall inflammation throughout the body. It affects children younger than age 5.

Lactose intolerance

Lactose intolerance means you can't fully digest milk sugar (lactose). Though it's generally not dangerous, the symptoms can be uncomfortable.

Legionnaires' disease

Legionnaires' disease, a severe form of pneumonia, is caused by bacteria that can live in water in air conditioning systems, showers and spas.

Listeria infection

Most people exposed to listeria don't become ill. But for those at risk of a listeria infection — a foodborne illness — the consequences can be severe.

Malaria

Malaria is one of the oldest diseases on Earth and is still one of the leading killers.

Mesenteric lymphadenitis

Mesenteric lymphadenitis is an inflammation of the lymph nodes in the tissue that attaches various organs to your abdominal wall (mesentery). It mainly affects children.

Milk allergy

Milk allergy can cause hives, wheezing and gastrointestinal problems. Avoidance is the primary treatment, but the good news is that many children outgrow milk allergy.

Myocarditis

Myocarditis is a disease in which the heart muscle becomes inflamed and swollen, often as the result of an infection.

Nicotine dependence

Breaking your addiction to nicotine is difficult and takes commitment, support and time. But doing so can make a huge difference in your overall health.

Norovirus infection

Noroviruses cause an intestinal flu-like illness that typically resolves within days. Norovirus infection is highly contagious, especially in closed settings like hospitals and cruise ships.

Ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) — Comprehensive overview covers symptoms, treatment of this complication of infertility treatment.

Peanut allergy

Peanut allergy can be serious. Find out what you need to know to prevent a life-threatening reaction.

Peritonitis

Peritonitis is an infection of the membrane that lines your inner abdominal wall and covers the organs within your abdomen (peritoneum).

Plague

Plague is a disease carried by rats and other rodents. The risk of developing plague is low, and most cases occur in Africa.

Porphyria

Porphyria is a group of inherited disorders that result from buildup of natural chemicals call porphyrins, which can cause nervous system and skin problems.

Premenstrual syndrome (PMS)

Premenstrual syndrome (PMS) can make you miserable in the days before your monthly period. Here's how to handle it — bloating, depression and all.

Preterm labor

Preterm labor — Comprehensive overview covers the symptoms, treatment and prevention of preterm labor.

Primary biliary cirrhosis

Primary biliary cirrhosis begins with inflammation in the liver's small bile ducts, but eventually can lead to damage and scarring in the liver itself.

Primary sclerosing cholangitis

Primary sclerosing cholangitis causes inflammation and scarring within the bile ducts of your liver, eventually affecting your liver's ability to do its job properly.

Proctitis

Proctitis is an inflammation of the lining of the rectum.

Pseudomembranous colitis

Pseudomembranous colitis is an inflammation of the colon that occurs most often in people using antibiotics.

Radiation sickness

Radiation sickness is the effect of high doses of radiation on the body. The severity of illness depends on how much radiation the body absorbs.

Reye's syndrome

Reye's syndrome is a rare but serious condition linked to giving children aspirin to treat viral infections.

Roseola

Roseola is a common infection of childhood. The condition causes a fever that lasts several days, followed by a rash on the trunk and neck.

Rotavirus

Rotavirus causes severe diarrhea in infants and children. Most cases can be treated at home with extra fluids.

Serotonin syndrome

Serotonin syndrome — caused by mixing some antidepressants and other medications — can be life-threatening if left untreated.

Severe acute respiratory syndrome (SARS)

Severe acute respiratory syndrome (SARS) has sickened people worldwide. Although effective treatments aren't yet available, common-sense precautions may help you avoid infection.

Shellfish allergy

Shigella infection

Shigella infection (shigellosis) is a disease that causes diarrhea. Young children are most likely to get the disease, but it can spread to anyone.

Smallpox

Smallpox, one of the oldest and most devastating of human diseases, was eradicated worldwide by 1980.

Social anxiety disorder

Intense fear and avoidance of social situations can be debilitating. Take action to avoid long-term consequences caused by worry and isolation.

Swine flu (H1N1 flu)

Swine flu — Comprehensive overview covers swine flu symptoms, tests, treatment and prevention.

Tapeworm infection

Tapeworms most commonly enter your body through contaminated food or water. Symptoms aren't always present, but the prognosis is good with prompt diagnosis and treatment.

Trichinosis

Trichinosis is a roundworm infection you get from eating undercooked, infected pork or other meats. Medications can eliminate the parasite and treat symptoms.

Tularemia

Tularemia is a rare, highly infectious disease spread by insects and wild animals. Landscapers, hunters and laboratory workers are especially at risk.

Typhoid fever

Although rare in industrialized nations, typhoid fever is a serious threat in many parts of the world. Learn how to stay safe when you travel.

Ulcerative colitis

Ulcerative colitis is a form of inflammatory bowel disease (IBD) — a serious inflammation of the digestive tract that can cause abdominal pain and diarrhea.

Vitamin deficiency anemia

Lacking certain vitamins can lead to vitamin deficiency anemia. Find out which vitamins are linked to this condition.

Whipple's disease

Whipple's disease is a rare bacterial infection that affects primarily the gastrointestinal system, and can be treated successfully with antibiotics.

Zollinger-Ellison syndrome

In Zollinger-Ellison syndrome, tumors in the pancreas or duodenum secrete a hormone called gastrin that leads to excessive stomach acid and ulcers.

Jun. 11, 2013