Signs of dehydration from diarrhea

Loose stools can remove fluid and body salts faster than you replace them. Vomiting, fever, hot weather, or difficulty drinking can increase the loss. Early signs include thirst, a dry or sticky mouth, darker urine, reduced urination, tiredness, and light-headedness when standing. More serious dehydration can cause confusion, fainting, a fast heartbeat, or very little urine.

Diarrhea itself may have many causes, including gastroenteritis. Dark urine can support concern about fluid loss, but urine colour alone cannot confirm dehydration.

Take frequent small sips of an oral rehydration solution, following its preparation instructions. Continue suitable food as tolerated and avoid relying on alcohol or very sugary drinks. Monitor urination, alertness, thirst, and the frequency of diarrhea. Children, older adults, pregnant people, and anyone with a long-term illness may need advice sooner.

Get urgent medical care for confusion, fainting, severe weakness, inability to keep fluids down, blood in stool, severe abdominal pain, or very little or no urine. Seek prompt advice when diarrhea is persistent, the person is becoming drowsy, or dehydration signs do not improve with fluids.

Ask: Which rehydration drink is suitable? How much should I take? Could medicines or another illness be contributing? What signs mean I need an intravenous fluid assessment? When should diarrhea be tested?