There is any other change in the person's alertness (for example, confusion or seizures).
The person has a fever over 102 °F.
You notice symptoms of heatstroke (like rapid pulse or rapid breathing).
The person's condition does not improve or gets worse despite treatment.
Drink plenty of fluids every day, even when you are well. Drink more when the weather is hot or you are exercising.
If anyone in your family is ill, pay attention to how much they are able to drink. Pay close attention to children and older adults.
Anyone with a fever, vomiting, or diarrhea should drink plenty of fluids. DO NOT wait for signs of dehydration.
If you think you or someone in your family may become dehydrated, call your health care provider. Do this before the person becomes dehydrated.
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: Mosby Elsevier; 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: Saunders Elsevier; 2011:chap 54.
Santillanes G. Claudius I. Rehydration Techniques in Infants and Children. In: Roberts: Roberts and Hedges' Clinical Procedures in Emergency Medicine. 6th ed. Philadelphia, Pa: Saunders Elsevier; 2013:chap 19.
Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.