Vomiting, diarrhoea, and excessive gas are most often due to a stomach infection or food-related irritation, and the main focus is to prevent dehydration. Start taking oral rehydration solution (ORS) in small, frequent sips, drink plenty of fluids like water or coconut water, and eat light foods such as rice, curd, and bananas while avoiding oily, spicy, and outside food; rest well and avoid self-starting antibiotics, though a doctor may suggest medicines to control vomiting or probiotics if needed. Most cases improve within 1-2 days, but you should seek medical care if symptoms are severe, persist beyond 2 days, or if you notice warning signs like high fever, blood in stool, inability to keep fluids down, or reduced urination.