Yes, this is normal. The Nexpro HP Kit contains strong antibiotics and an acid reducer. At day three, the H. pylori infection is still being treated, and your stomach lining needs more time to fully heal. Furthermore, the antibiotics can temporarily disrupt your gut bacteria, commonly causing side effects like gas, bloating, or mild nausea. It is crucial to complete the entire 14-day course to completely eradicate the bacteria and prevent resistance. However, if you experience severe abdominal pain, persistent vomiting, severe watery diarrhea, or an allergic reaction (like a rash), please contact your doctor immediately.