Upset stomach may occur due to indigestion, acidity, a viral stomach infection, food poisoning, overeating, contaminated food, stress, or irregular eating habits. Symptoms can include stomach discomfort, bloating, nausea, gas, loose motions, abdominal cramps, heaviness, or a burning sensation, depending on the underlying cause. The most appropriate medicine depends on whether the problem is related to acidity, gas, diarrhoea, infection, or indigestion. Antacids may help with acidity or burning, probiotics may help digestion after a stomach infection, and oral rehydration solutions may help prevent dehydration during loose motions or vomiting. Eating light foods such as rice, curd, banana, toast, khichdi or soups may help the stomach settle more comfortably. Sufficient hydration, proper rest, and avoiding oily, spicy, heavy or outside food for some time may also speed up recovery. Avoid drinking, smoking and excessive tea or coffee until the stomach feels normal again. Inform a doctor if severe abdominal pain, repeated vomiting, blood in stool, high fever, dehydration, black stool, or persistent stomach symptoms continue despite supportive care.