Hi. Thanks for your query. Read the history and understood the problems. History of Crayola Crayon green stools is indicative of an active and atypical infection as usually seen in infants . This is casing you the pain in the upper middle abdomen along with Gastritis. Anyways , the known history of IBS complicates the problem more. I would advise you the following : First of all the tests before the antibiotics are started to get the correct results. - Stool: culture and sensitivity; routine and microscopy, occult blood. - Blood : CBC, Sugar , thyroid , liver and kidney functions - Urine test -Ultrasonography -Colonoscopy. Your Doctor will start a course of an antibiotic which is active against the bacteria that produce green stools; metronidazole, probiotic are a must to restore the gastric flora, symptomatic and supportive. I am sure this is going to help you a lot . Once the Problems come under control, go for further tests if required. Continue probiotic for a long tine. Have control over stress and anxiety