Dehydration
Dehydration happens when the body loses more fluid than it takes in. This can occur after vomiting, diarrhoea, fever, heavy sweating, exercise, hot weather, alcohol use, or simply not drinking enough fluids. Mild dehydration may cause thirst, dry mouth, tiredness, dizziness, headache, dark yellow urine, or passing urine less often than usual.
About Dehydration
Dehydration Overview
Older adults, pregnant people, and people with long-term conditions such as diabetes may become dehydrated more quickly or find it harder to recognise the signs. Children and babies need particular care, especially if they have vomiting, diarrhoea, fewer wet nappies, no tears when crying, a dry mouth, fast breathing, unusual drowsiness, or a sunken soft spot on the head.
Mobi Doctor can help with non-emergency advice if you are concerned about mild dehydration, recent fluid loss, travel-related illness, diarrhoea, vomiting, heat exposure, or whether your symptoms need further medical care. A doctor can review your symptoms, medical history, current medicines, risk factors, and how long the problem has been present before advising on the safest next step.
Seek urgent local medical care if you or someone else cannot keep fluids down, is confused or very drowsy, has fainting, seizures, rapid breathing, a fast heartbeat, very little or no urine, severe weakness, signs of shock, or symptoms of dehydration in a baby or young child. Severe dehydration needs immediate medical treatment.
Common types of Dehydration we treat
Pick the symptom or sub-condition that best matches what you're experiencing.
Can this be treated online?
Mild dehydration symptoms can often be assessed online, including headaches, dizziness, dry mouth, fatigue, nausea, dark urine, increased thirst, and mild weakness. Treatment advice may include hydration guidance, electrolyte recommendations, and further assessment based on your symptoms and possible underlying causes.
Prescriptions & safety
Our licensed doctors may prescribe medication, issue repeat prescriptions or provide referrals where clinically appropriate and medically safe following an online consultation. Prescriptions are never guaranteed or issued automatically, and treatment decisions are always based on the patient’s symptoms, medical history and clinical assessment.
Some medicines, controlled substances and higher-risk treatments cannot be prescribed through online consultations. In certain cases, patients may instead be advised to seek in-person assessment, testing or emergency medical care where appropriate.
When to seek urgent in-person care
If you are experiencing any of the following with your dehydration, call 112 or go to your nearest A&E immediately. Online care is not appropriate for emergencies.
- Fainting or loss of consciousness
- Confusion or severe dizziness
- Inability to keep fluids down
- Chest pain or breathing difficulty
- Severe weakness or inability to stand
- Signs of severe dehydration, including very little urine output
- Rapid heartbeat or severe low blood pressure symptoms
- Rapidly worsening symptoms or severe vomiting
Dr. Chrysoula I. Liakou MD, PhD
Ready To Speak With A Doctor?
Feeling Dizzy, Weak, Or Dehydrated? Online assessment may help with dehydration symptoms linked to illness, heat exposure, vomiting, diarrhoea, travel, or poor fluid intake. Guidance may include hydration support, recovery advice, and recommendations based on symptom severity.
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