SIBO stands for “small intestinal bacterial overgrowth.” It’s normal and healthy to have bacteria living in your small intestine, but too many can cause problems with your digestion — especially if they’re the wrong kind. The wrong bacteria can overwhelm the beneficial bacteria that you need to be there, and they can upset your digestive system by feeding on products that aren’t meant for …

A sarcoma is a malignant (cancerous) tumor that develops in bone and/or soft tissue. Soft tissues support other body structures and include: Muscle. Fat. Tendons. Cartilage. Ligaments. Blood vessels. Nerves. Sarcomas are rare, making up only 1% of all adult cancer diagnoses and about 15% of childhood cancer diagnoses. Approximately 16,000 sarcomas are diagnosed in the United States each year (around 4,000 bone sarcomas …

Sarcoidosis is a condition that causes your immune system to overreact and make lumps or nodules called granulomas. Depending on location and size, granulomas can cause mild to severe symptoms or no symptoms at all. In some cases, they can turn into fibrosis, causing permanent lung scarring. Granulomas can be found almost anywhere in your body, but they’re most commonly found …

Seasonal affective disorder (SAD) is a type of depression triggered by a change in seasons, usually when fall starts. This seasonal depression gets worse in the late fall or early winter before ending in the sunnier days of spring. You can also get a mild version of SAD known as the “winter blues.” It’s normal to feel a little down …

Sacroiliitis is painful inflammation in the joints where your spine connects to your pelvis (your sacroiliac joints). It causes pain in your lower back, butt (your buttock muscles) or legs. A joint is a place in your body where two bones meet. Your sacroiliac joints are the connection between your spine and pelvis. Specifically, they’re the place where the sacrum (the …

Your spleen is a tender, fist-sized organ in your upper left belly (abdomen). It’s primarily responsible for storing and filtering blood. It stores and filters 25% of your red blood cells and platelets at any given time, while helping to make white blood cells to fight infections. The inner “pulp” of the spleen that performs these functions is enclosed in a thin capsule of muscular tissue, with blood …

Rumination syndrome (also known as rumination disorder or merycism) is a feeding and eating disorder in which undigested food comes back up from a person’s stomach into his or her mouth (regurgitation). Once the food is back in the mouth, the person may chew it and swallow it again, or spit it out. This behavior usually occurs after every meal, …

Rotavirus is a contagious gastrointestinal (GI) infection that causes inflammation of the stomach and intestines (gastroenteritis). This can lead to severe diarrhea and vomiting, especially in young children. Kids tend to get rotavirus during the winter and spring. It spreads when they come in contact with the poop (stool) of someone who has it and then touch their own mouth. …

A rotator cuff tear is an injury to your rotator cuff that can cause shoulder pain and the inability to use your arm. Your rotator cuff is a group of muscles and tendons in your shoulder. They help you lift and move your arms away from your body. Your rotator cuff keeps the ball of your upper arm bone (humerus) in the …

Roseola is a viral infection that mostly affects babies and young children, typically in the first two years of life. Roseola causes a sudden, high fever that lasts about three to four days. After the fever breaks, some children develop a rash that lasts two to four days. Most children can recover at home in a week or less. Roseola is often harmless and doesn’t lead …