Dehydration fluid replacement: what to know

Dehydration means the body loses more fluid than it takes in. Thirst, dry mouth, tiredness, dizziness, and dark urine may appear. Drinking a large amount quickly is less helpful when nausea is present; small regular sips are easier to keep down.

Water may suit mild loss. After heavy sweating, vomiting, or diarrhoea, an oral rehydration solution can replace water and electrolytes in a measured balance. Follow its directions. Dark urine can suggest low intake, although it has other possible causes.

Rest and sip water or an oral rehydration drink regularly. After vomiting, restart with tiny sips. Eat light foods when able and avoid alcohol. If you have kidney, heart, or liver disease, ask a clinician how much to drink.

Dehydration may accompany gastroenteritis or heat exhaustion, so address the illness or exposure causing fluid loss as well as replacing fluid.

Seek prompt advice if you cannot keep fluids down, pass very little urine, feel faint when standing, or remain weak despite sipping. Get urgent help for confusion, severe drowsiness, collapse, breathing trouble, or blood in vomit or stool.

Ask which drink suits your symptoms, whether regular medicines affect fluid balance, and what signs require examination or blood tests.