Tea and dehydration: what to know

Most tea contributes fluid, so a cup can count towards hydration. However, strong caffeinated tea may worsen palpitations, nausea, or sleep problems, and very hot drinks can be uncomfortable when you are unwell. Tea does not replace salts lost through repeated diarrhoea, vomiting, or heavy sweating.

Dehydration can cause thirst, dry mouth, headache, dizziness, tiredness, constipation, and darker urine. Gastroenteritis and heat exhaustion are common settings for fluid loss, but symptoms may need another explanation if they persist.

Sip water regularly if you can drink normally. If vomiting or diarrhoea has caused substantial fluid loss, use an oral rehydration solution as directed; it supplies a balance of water and salts. Choose caffeine-free tea if tea feels soothing, and let it cool to a comfortable temperature.

Take small sips rather than a large drink when nausea is present. Rest in a cool place after heat exposure. People with kidney or heart conditions, or a prescribed fluid limit, should follow their clinician's plan rather than increasing drinks independently.

Seek urgent medical help for confusion, fainting, severe dizziness, inability to keep fluids down, very little urine, severe abdominal or flank pain, or worsening symptoms after heat exposure. Arrange prompt review if dark or cloudy urine, burning, or fever continues.

Ask which drinks suit your symptoms, whether you need oral rehydration, how to manage fluids with your health conditions, and whether a urine test is needed for persistent colour or urinary changes.