It's definitely the garlic itself. I tried out garlic capsules (which ended up causing a die-off reaction) and they also upset my stomach pretty bad. I think it's the volatile oils in the garlic that irritate the stomach lining. Not to discourage you, but just be careful you don't try to fix one problem and end up causing another. My sister screwed up her stomach by taking morphine pills and now she has to take a rx stomach med every day. The stomach is actually one of the most resilient organs but you can end up giving yourself an ulcer if you're constantly irritating it. Be careful.