High fever along with dehydration, vomiting, and possible food poisoning is usually caused by contaminated food or water, stomach infection, or a viral illness affecting the digestive system. The most important part of treatment is preventing dehydration because repeated vomiting and fever can quickly reduce the body's water and salt levels. Drink fluids slowly and frequently, such as ORS (oral rehydration solution), coconut water, rice water, lemon water with a little salt and sugar, or plain water in small sips if vomiting continues. Eat light and easy-to-digest foods like bananas, toast, rice, khichdi, curd, soup, or boiled potatoes, and avoid oily, spicy, junk, or outside food until recovery. Rest well and avoid heavy physical activity. Medicines like paracetamol may help reduce fever and body pain if taken in the correct dose, but antibiotics or anti-vomiting medicines should not be taken without medical advice because treatment depends on the exact cause. It is very important to seek medical attention immediately if you have severe stomach pain, blood in vomit or stool, confusion, reduced urination, dizziness, difficulty breathing, a very high fever, inability to drink fluids, or symptoms lasting more than one or two days, because severe dehydration or infection may require hospital treatment. In many mild cases, proper hydration, rest, and careful eating help the body recover naturally within a few days.