For a suspected stomach infection with vomiting and diarrhea, the most critical step is preventing dehydration. Drink Oral Rehydration Salts (ORS) or electrolyte solutions in small, frequent sips. You can take an over-the-counter antiemetic (like Ondansetron) to control vomiting and probiotics to help restore gut health. Avoid anti-diarrheal medications (like loperamide) if you have a fever or bloody stools, as they can worsen infections. Please do not take antibiotics without a doctor's prescription. Stick to a bland diet, and seek immediate medical care if you cannot keep fluids down, experience severe abdominal pain, high fever, or notice blood in your stool.