There are many reasons why you might have both diarrhea and sores in your mouth. A simple virus may lead to both things. But there are some inflammatory conditions that can cause both diarrhea and mouth sores, including Crohn's Disease and Behcet's disease. If your symptoms persist or are severe, check with your doctor to see what is causing them.
While the list below can be considered as a guide to educate yourself about these conditions, this is not a substitute for a diagnosis from a health care provider. There are many other medical conditions that also can be associated with your symptoms and signs. Here are a number of those from MedicineNet:
Food poisoning is common, but can also be life threatening. The symptoms for food poisoning are fever, abdominal pain, headache, diarrhea, nausea and vomiting. Food poisoning has many causes, for example, chemicals (from toxic fish or plants) and bacteria (Staphylococcus aureus or Salmonella). Treatment of food poisoning depends upon the cause.
Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome (IBS) is a GI (gastrointestinal) disorder with signs and symptoms that include abdominal pain, bloating, increased gas (flatulence), abdominal cramping, diarrhea, constipation, and food intolerance.Two new tests are now available that may help diagnose irritable bowel syndrome with diarrhea and constipation (IBS-M) irritable bowel syndrome with diarrhea (IBS-D), and irritable bowel syndrome with constipation (IBS-C). Treatment for IBS includes diet changes, medications, and other lifestyle changes to manage symptoms.
Travelers' diarrhea is generally contracted by eating contaminated food or drinking contaminated water. Food is the primary source of travelers' diarrhea. Enterotoxigenic E. coli is the cause of up to 70% of all cases of travelers' diarrhea. There are five unique classes of E. coli that causes gastroenteritis. Other bacteria responsible for travelers' diarrhea include Campylobacter, jejuni, shigella, and salmonella. Viruses such as rotavirus and Norwalk virus (norovirus) and giardia lamblia a parasite may cause travelers' diarrhea. Prevention is careful eating and drinking of water.
Gastroenteritis (Stomach Flu)
Stomach flu (gastroenteritis) is a term referred used to describe a variety of gastrointestinal problems. The most common signs and symptoms of gastroenteritis are nausea, vomiting, diarrhea, and abdominal pain. The most common cause of gastroenteritis in the United States is Norovirus. Other causes of gastroenteritis include Rotavirus, Astrovirus, Adenovirus, and Sapovirus. There are bacterial causes of gastroenteritis such as Salmonella, Shigella, Campylobacter Aeromonas, E. coli, Clostridium, Vibrio, Campylobacter, and Yersinia spp. Parasites that cause gastroenteritis include Giardia, Cryptosporidium, Cyclospora, and Entamoeba. Treatment for gastroenteritis is generally home remedies such as keeping hydrated to prevent dehydration. At times, hospitalization may be necessary if dehydration occurs.
At MedicineNet, we believe it is important to take charge of your health through measures such as a living healthy lifestyle, practicing preventative medicine, following a nutrition plan, and getting regular exercise. Understanding your symptoms and signs and educating yourself about health conditions are also a part of living your healthiest life. The links above will provide you with more detailed information on these medical conditions to help you inform yourself about the causes and available treatments for these conditions.