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Dehydration
Dehydration is when the body loses more fluid than it takes in. It is common in hot weather and with vomiting or diarrhoea, and ranges from mild thirst to a medical emergency.
Causes & risk factors
- Vomiting and diarrhoea
- High fever and sweating in hot weather
- Not drinking enough fluids
- Uncontrolled diabetes
- Certain medicines (diuretics)
Common symptoms
- Thirst and dry mouth
- Passing little, dark urine
- Dizziness, especially on standing
- Tiredness
- Headache
- Sunken eyes (in severe cases)
Tests & diagnosis
- Mostly a clinical assessment
- Electrolytes
- Kidney function (RFT)
- Creatinine
- Urine test
Treatment & management
- Drinking fluids and oral rehydration solution (ORS)
- Treating the cause (vomiting, diarrhoea, fever)
- Small frequent sips if nausea is a problem
- IV fluids in hospital for severe dehydration
- Extra care in children and older adults
When to see a doctor urgently
- Confusion, fainting or very little urine — urgent
- Being unable to keep any fluids down
- Signs of dehydration in a baby or older person
- Severe or ongoing diarrhoea and vomiting
Frequently asked questions
What is the best drink for dehydration?
Oral rehydration solution (ORS) is ideal because it replaces both water and salts. Plain water helps for mild cases, but avoid sugary or fizzy drinks.
Who is most at risk of dehydration?
Young children, older adults and people with diabetes or ongoing vomiting and diarrhoea are most at risk and can worsen quickly, so they need prompt fluids.
Explore more
Sources & further reading
- World Health Organization (WHO)
- MedlinePlus — U.S. National Library of Medicine
- Ministry of Health & Family Welfare, India
- Indian Council of Medical Research (ICMR)
Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.