Gastroenteritis is a general term for a group of conditions that are usually caused by infection and produce symptoms such as loss of appetite, nausea, vomiting, mild-severe diarrhea, cramps and discomfort in the abdomen. Electrolytes, particularly sodium and potassium , are lost along with body fluids. There is so many different ways to have this illness, Microorganisms, E-coli, Campylobacter, shigella, and Salmonella. Besides bacteria, several viruses (Norwalk & coxsackie). Certain parasites can cause this as well,, Giardia lamblia, another parasite called Cryptosporidium both of these are acquired by drinking contaminated waters.
Gastroenteritis may result from eating chemical toxins found in sea foods, in plants, ( mushrooms, and potatoes),,or in contaminated foods. Also lactose intolerance, accidentally ingesting heavy metals such as arsenic, lead, mercury, or cadmium.
Usually the only treatment for gastroenteritis is to drink adequate fluids. Even in a person who is vomiting should drink small amounts of fluids because fluids correct dehydration, which in turn may help stop the vomiting. If vomiting is prolonged or the person becomes dehydrated intravenous fluids and electrolytes may be needed such as teas, sports drinks, carbonated beverages, fruit drinks..
As the symptoms improve the person may gradually add bland foods such as ---cooked cereals, bananas, rice, apple sauce, toast, pudding, jellos to the diet. this should help with the diarrhea in about 12-24 hours however with a serious bacterial infection (causing blood to be in the stool )You need to get meds to treat this type infection you might try some OTC meds where you live ask the pharmacist what they might have to offer you for this condition however don't mess around to long this could be a fatal mistake do seek some professional help even at a free health clinic in your area or ER what ever you have to do .