Dehydration and no appetite: what to know

When the body lacks fluid, dry mouth, nausea, tiredness and headache can make food less appealing. Vomiting, diarrhoea, heat exposure or an illness such as Gastroenteritis may start the fluid loss and appetite change together. Dark urine, passing urine less often, dizziness or a sticky mouth can support dehydration, but appetite loss has many other causes. A urinary infection, constipation or another illness may need separate assessment.

Take small, frequent sips of water or an oral rehydration drink. If nausea is present, pause briefly after a sip and try again rather than drinking a large amount at once. Choose easy foods such as soup, yoghurt, rice, toast or fruit when you can tolerate them. Rest somewhere cool, avoid alcohol, and keep track of whether you are drinking and passing urine. People with heart, kidney or liver disease, or fluid restrictions, should ask a clinician how much to drink.

Seek urgent care if you cannot keep fluids down, become confused, are unusually sleepy, faint, have severe weakness, or pass very little urine. Get prompt medical advice for persistent appetite loss, repeated vomiting or diarrhoea, severe abdominal pain, fever, or signs of Heat Exhaustion. A clinician may check hydration, blood pressure, urine and the illness causing the fluid loss.

Ask: Could a medicine or illness be affecting my appetite? Which rehydration drink is suitable for me? What symptoms should prompt same-day care?