Nausea is a common sign of dehydration (lack of water). When your body doesn’t have enough water, your digestion slows down and can make you feel sick. Dehydration can happen quickly when you’re in a hot environment or have severe diarrhea or vomiting. If you feel nauseous and don’t know why, consider whether you’ve had enough water to drink. Even mild dehydration can quickly become serious. Other symptoms to watch for include: Confusion or irritability Dark yellow urine or not urinating Dizziness or feeling faint Dry or sticky mouth Extreme thirst Fever Rapid heartbeat No tears when crying (in babies) DispatchHealth provides in-home treatment for dehydration, including intravenous (IV) fluids. Our medical team comes to you, so you don’t have to travel for expert care.