What causes foamy stool?
Inflammatory Bowel Disease (IBD)
I have gone through your query. You pass foamy stool usually in afternoon. This has been going on for last one month. After course of O2 you get it again. There might be some Inflammatory condition going in your gastro-intestinal tract.
It may be due to various causes like lactose intolerance, allergy to gluten protein (Wheat protein), vitamin deficiency or infections. As symptoms stopped on taking O2, I usually advise my patients, antibiotics like Ciprofloxacin 500 mg twice daily and metronidazole 400 mg thrice daily for 7 more days.
If after the course, problem recurs, you need investigations like Blood test for Antiendomysial antibodies, and if tests come positive gastroscopy and biopsy may be required. You will need to visit a local Gastroeneterologist for clinical examinations and treatment.
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