Inflammatory bowel disease (IBD) involves chronic inflammation of all or part of your digestive tract. IBD primarily includes ulcerative colitis and Crohn's disease. IBD can be painful and debilitating, and sometimes leads to life-threatening complications.
Ulcerative colitis (UL-sur-uh-tiv koe-LIE-tis) is an inflammatory bowel disease that causes long-lasting inflammation in part of your digestive tract. Symptoms usually develop over time, rather than suddenly. Ulcerative colitis usually affects only the innermost lining of your large intestine (colon) and rectum. It occurs only through continuous stretches of your colon.
Crohn's disease is an inflammatory bowel disease that causes inflammation anywhere along the lining of your digestive tract, and often spreads deep into affected tissues. This can lead to abdominal pain, severe diarrhea and even malnutrition. The inflammation caused by Crohn's disease can involve different areas of the digestive tract in different people.
Collagenous colitis (kuh-LAJ-uh-nus) and lymphocytic colitis also are considered inflammatory bowel diseases, but are usually regarded separately from classic inflammatory bowel disease.

Irritable bowel syndrome (IBS) is a common disorder that affects your large intestine (colon). Irritable bowel syndrome commonly causes cramping, abdominal pain, bloating gas, diarrhea and constipation. Despite these uncomfortable signs and symptoms, IBS doesn't cause permanent damage to your colon.
Most people with IBS find that symptoms improve as they learn to control their condition. Only a small number of people with irritable bowel syndrome have disabling signs and symptoms.
Fortunately, unlike more-serious intestinal diseases such as ulcerative colitis and Crohn's disease, irritable bowel syndrome doesn't cause inflammation or changes in bowel tissue or increase your risk of colorectal cancer. In many cases, you can control irritable bowel syndrome by managing your diet, lifestyle and stress.

Ice cream headaches are brief, stabbing headaches that can happen when you eat or drink something cold. Ice pops, slushy frozen drinks, ice cream, and other cold foods and drinks can have the same "brain-freeze" effect.
But there's good news. Most ice cream headaches are gone in the time it would take you to say their medical name — "headache attributed to ingestion or inhalation of a cold stimulus."

Ichthyosis vulgaris (ik-thee-O-sis vul-GAY-ris) is an inherited skin disorder in which dead skin cells accumulate in thick, dry scales on your skin's surface.
The scales of ichthyosis vulgaris, sometimes called fish scale disease or fish skin disease, can be present at birth, but usually first appear during early childhood. Sometimes, mild cases of ichthyosis vulgaris go undiagnosed because they're mistaken for extremely dry skin.
Most cases of ichthyosis vulgaris are mild, but some are severe. Sometimes other skin diseases, such as the allergic skin condition eczema, are associated with ichthyosis vulgaris. No cure has been found for ichthyosis vulgaris, and treatments focus on controlling the condition.

Hay fever, also called allergic rhinitis, causes cold-like signs and symptoms, such as a runny nose, itchy eyes, congestion, sneezing and sinus pressure. But unlike a cold, hay fever isn't caused by a virus. Hay fever is caused by an allergic response to outdoor or indoor allergens, such as pollen, dust mites or pet dander.
Hay fever can make you miserable and affect your performance at work or school and interfere with leisure activities. But you don't have to put up with annoying symptoms. Learning how to avoid triggers and finding the right treatment can make a big difference.

Indigestion — also called dyspepsia or an upset stomach — is a general term that describes discomfort in your upper abdomen. Indigestion is not a disease, but rather some symptoms you experience, including abdominal pain and a feeling of fullness soon after you start eating. Although indigestion is common, how you experience indigestion may differ from other people. Symptoms of indigestion may be felt occasionally or as often as daily.
Indigestion can be a symptom of another digestive disease. Indigestion that isn't caused by an underlying disease may be eased with lifestyle changes and medication.

Infant jaundice is a yellow discoloration in a newborn baby's skin and eyes. Infant jaundice occurs because the baby's blood contains an excess of bilirubin (bil-ih-ROO-bin), a yellow-colored pigment of red blood cells.
Infant jaundice is a common condition, particularly in babies born before 38 weeks gestation (preterm babies) and breast-fed babies. Infant jaundice usually occurs because a baby's liver isn't mature enough to get rid of bilirubin in the bloodstream. In some cases, an underlying disease may cause jaundice.
Treatment of infant jaundice often isn't necessary, and most cases that need treatment respond well to noninvasive therapy. Although complications are rare, severe infant jaundice or poorly treated jaundice can cause brain damage.

If getting pregnant has been a challenge for you and your partner, you're not alone. Ten to 15 percent of couples in the United States are infertile. Infertility is defined as not being able to get pregnant despite having frequent, unprotected sex for at least a year — or for at least six months if the woman is age 35 or older.
Infertility may be due to a single cause in either you or your partner, or a combination of factors that may prevent a pregnancy from occurring or continuing. Fortunately, there are many safe and effective therapies for overcoming infertility. These treatments significantly improve your chances of becoming pregnant.

Infectious diseases are disorders caused by organisms — such as bacteria, viruses, fungi or parasites. Many organisms live in and on our bodies. They're normally harmless or even helpful, but some organisms under certain conditions may cause disease.
Some infectious diseases can be passed from person to person. Some, however, are transmitted via bites from insects or animals. Others are acquired by ingesting contaminated food or water or other exposures in the environment.
Signs and symptoms vary, but often include fever and chills. Mild complaints may respond to home remedies, while some life-threatening infections may require hospitalization.
Many infectious diseases, such as measles and chickenpox, can be prevented by vaccines. Frequent and thorough hand-washing also helps protect you from infectious diseases.