Hi. Thanks for your query. Noted the history of pain in abdomen and getting icky taste in mouth like burning tuna, accompanied by vomiting or diarrhea, once was the vomit white and milky looking- light brown stools with dark brown spots. Since your problem is lasting for about a year it is necessary to have a proper clinical evaluation and examination by a Gastroenterologist and go for the following investigations and additional history: Tests of stool, blood and urine. Ultrasonography X-ray of the abdomen in standing position. Trial with an antibiotic, probiotic may help. Once the GI flora gets disturbed, the pathogenic bacteria produce toxins that go to the blood and secreted into the saliva to give that typical taste you have .