Can dehydration cause diarrhea?

Loose stools carry fluid and electrolytes out of the body. Vomiting, fever, reduced appetite, or hot weather can add to the loss. Gastroenteritis is one possible reason for diarrhea, but food intolerance, medicines, and other bowel problems can also be involved. Dehydration may then show as thirst, a dry mouth, tiredness, dizziness, or dark urine. See the condition guide for more detail on [Dehydration](/conditions/dehydration/).

Take frequent small sips of water or an oral rehydration drink. If nausea is present, try a sip every few minutes rather than drinking a large amount at once. Continue suitable food as tolerated, and avoid alcohol. Monitor urination and alertness. Dark urine can be a useful sign that you need more fluid; persistent symptoms may need assessment. Read about [Dark Urine](/symptoms/dark-urine/) if that is one of your symptoms.

Seek urgent medical help if you cannot keep fluids down, feel faint or confused, pass very little urine, have severe abdominal pain, or see blood in the stool. Contact a clinician promptly when diarrhea continues, affects an older adult or young child, or occurs with significant fever. These features can signal a need for examination and supervised rehydration.

Ask what may be causing the diarrhea, which rehydration product suits you, whether any medicine should be paused, and how to recognise worsening dehydration. Mention recent travel, new foods, antibiotics, medical conditions, and the pattern of urination.