context: Pseudomembranous colitis ( PMC) is inflammation in your colon that happens when there's too much of certain bacteria in your system. The most common bacterium that causes PMC is Clostridium difficile, or C. diff. PMC is also called antibiotic-associated colitis or C. difficilecolitis. Most of the time, it's a side effect of taking antibiotics. People in hospitals or nursing homes also can get PMC, especially if they've just had surgery or are receiving treatment for cancer. You're specifically at risk if you: Are over 65 Have been in an intensive-care unit ( ICU) Have burns on your body Have had a C-section or surgeries of the GI tract Have kidney problems Diseases of the colon such as inflammatory bowel disease or colorectal cancer Use chemotherapy drugs Use of drugs called proton-pump inhibitors, which lessen stomach acid Have had a previous C. diff infection It's rare for young children or infants to get PMC. It can take a day or two for PMC symptoms to show up after you start taking antibiotics. You may not have symptoms until a week or two after you've finished taking them. The most common signs are: Diarrhea that's watery, foul smelling, or bloody Dehydration Fever Nausea Pus in your stool Stomach cramps See your doctor if you've recently taken antibiotics and have diarrhea. You need medical help any time you have severe diarrhea with stomach cramps or blood or pus in your stool. In more serious cases of PMC, you may also have: Low blood pressure Low heart rate Weak pulse C. diff lives in soil, air, water, and feces and sometimes in foods like processed meats. You can get it when you touch a surface that has the bacteria on it and then put your hand near or in your mouth. Once it's in your body, C. diff makes a kind of poison. The good bacteria in your colon usually keep the amount of C. diff in your body under control, but antibiotics can kill the healthy bacteria and let C. diff grow too fast. This damages your colon and causes PMC. While practically any antibiotic can cause it, some are more likely to cause PMC than others. These include: Cephalosporins ( Cephalexin, Suprax) Clindamycin ( Cleocin) Fluoroquinolones ( Cipro, Levaquin) Penicillin (amoxicillin, ampicillin) PMC also can be related to: Changes in your diet Chemotherapy Hirschsprung disease (a condition that affects your colon) Kidney disease or kidney failure Malnutrition Recent bowel surgery Shock To find out if you have PMC, you may need one of these tests: Blood test to check your white blood cell count Imaging tests, like an X-ray or CT scan of your lower belly (for serious cases) Stool sample test to check for bacteria in your colon You also may have a colonoscopy or sigmoidoscopy, which are exams that look inside your colon with a thin flexible tube. Your doctor may take a tissue sample during the exam for testing. If an antibiotic caused the problem, your doctor may prescribe other antibiotics that help good bacteria grow back so your symptoms go away faster. These include: Fidaxomicin ( Dificid) Metronidazole ( Flagyl) Vancomycin You take these medications by mouth, through a vein, or through a tube in your stomach. Probiotics may be helpful in treating mild C. diff infections. But talk to your doctor before taking any. While receiving an antibiotic, you may also be given bezlotoxumab ( Zinplava). Given as a shot in a vein, this medicine helps reduce the recurrence of a C. diff infection. If your PMC is severe or keeps coming back, you may need: Extra rounds of antibiotics Fetal microbial transplant ( FMT), during which your doctor puts healthy stool from a donor into your system to help restore good bacteria Surgery to take out part of your colon (less than 1% of people with PMC need this.) If you're dealing with PMC symptoms, drink plenty of fluids like water or watered-down fruit juice to help flush out your system. Eat soft foods that are easy to digest like applesauce, rice, or bananas. Avoid high-fiber foods like nuts, beans, and veggies. Eat several small meals during the day instead of a few large ones, and stay away from fried, spicy, or fatty foods. They can irritate your stomach and make your symptoms worse. Wash your hands regularly to keep C. diff from spreading and getting back into your system.