Dehydration occurs when your body does not have as much water and fluids as it should.
Dehydration can be mild, moderate, or severe, based on how much of your body's fluid is lost or not replaced. Severe dehydration is a life-threatening emergency.
You can become dehydrated if you lose too much fluid, don't drink enough water or fluids, or both.
Your body may lose a lot of fluid from:
You might not drink enough fluids because:
Older adults and people with certain diseases, such as diabetes, are also at higher risk for dehydration.
Signs of mild to moderate dehydration:
Signs of severe dehydration:
Your health care provider will look for these signs of dehydration:
Your doctor may do lab tests:
To treat dehydration:
Dehydration caused by a stomach virus should get better on its own after a few days.
If you notice signs of dehydration and treat it quickly, you should recover completely.
If untreated, severe dehydration may cause:
You should call 911 if:
Chen L. Infectious diarrheal diseases and dehydration. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, PA: Elsevier Mosby; 2009:chap 171.
Greenbaum LA. Deficit therapy. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Mosby; 2011:chap 54.
Santillanes G. Claudius I. Rehydration techniques in infants and children. In: Roberts JR, Hedges JR, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine. 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 19.
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.
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