Staying Hydrated When Sick: What to Drink and When to Get Help

Person resting with glass of water and lemon, herbal tea, and electrolyte drinks for illness recovery

Illness can make drinking harder just when fever, sweating, vomiting, or diarrhea increase fluid loss. A cold with a normal appetite is different from a stomach bug that makes every sip difficult. The useful goal is to keep taking in fluid you can tolerate and notice signs that you need help.

Hydration prevents and treats fluid loss; it does not cure an infection or guarantee a faster recovery. This guide explains what to drink, when an oral rehydration solution may be useful, and when symptoms need medical assessment. The NHS dehydration guide and its diarrhea and vomiting guidance inform the practical advice below.

Why Hydration Can Be Harder During Illness

There is no percentage increase that fits every illness. Your needs depend on what you lose, how much you can drink, your age, and any condition or medicine that affects fluid balance.

Fever and sweating: A high temperature and sweating can increase fluid loss. Offer drinks regularly and watch whether thirst, urine output, and other symptoms change. A fixed number of milliliters per degree of fever is not a reliable home target.

Congestion and a sore throat: These can make drinking less appealing. Warm or cool drinks may feel better, depending on your preference. A stuffy nose alone does not mean you need a large extra volume of water.

Vomiting and diarrhea: Repeated episodes can remove water and salts while making drinking difficult. The number of episodes, whether fluid stays down, and signs of dehydration matter more than an estimated loss per episode.

Less appetite and nausea: If you eat and drink less, your usual meals provide less fluid too. Small, frequent sips may be easier than a full glass.

Medicines and other conditions: Some medicines, including diuretics, affect fluid balance. If you have kidney or heart disease, diabetes, or a prescribed fluid limit, ask your clinician how to handle illness rather than following a generic drinking target.

The Best Fluids to Drink When Sick

Choose fluids you can tolerate. With repeated vomiting or diarrhea, replacing salts may matter too.

Water: Your Foundation

Water is a simple choice when you can drink normally. Cool or warm water is fine; choose the temperature that feels comfortable. With repeated vomiting or diarrhea, water alone may not replace the salts being lost.

Pro tip: If plain water feels unappealing, try adding a squeeze of lemon or a few slices of cucumber for subtle flavor without added sugar.

Electrolyte Solutions

With vomiting or diarrhea, you can lose both water and salts. An oral rehydration solution (ORS) contains a measured combination designed to replace them. Ask a pharmacist which product is appropriate for you or your child, and mix it exactly as directed.

ORS versus sports drinks: A pharmacy ORS is the more suitable choice when vomiting or diarrhea is causing dehydration. Sports drinks are formulated for exercise and are not equivalent to ORS. The CDC's norovirus guidance notes that sports drinks may not replace important minerals in this setting.

Avoid improvising an ORS recipe: Mixing by eye can change the balance of sugar and salt. Use a correctly prepared pharmacy product when one is needed; ask a pharmacist or clinician if it is unavailable.

Warm Broths and Soups

Soup and broth can contribute fluid and be comforting when you feel able to eat. They may also provide some salt and calories. Choose what you can tolerate; neither is a treatment for an infection or a substitute for ORS when substantial fluid is being lost.

Bone broth is another food and fluid option, but claims that its collagen speeds immune or gut recovery are not established.

Herbal Teas

Caffeine-free herbal teas can be a pleasant way to take in fluid. Their ingredients do not replace medical treatment or ORS when needed:

Ginger tea may feel soothing if nausea makes plain water unappealing.

Peppermint tea is another option if you enjoy it and it agrees with your stomach.

Chamomile tea offers a warm, caffeine-free drink before rest.

Honey and lemon tea may feel soothing on a sore throat. Do not give honey to a baby under one year. NHS.

Coconut Water

Coconut water is a drink some people enjoy, but its mineral content varies and it is not a replacement for ORS during significant vomiting or diarrhea. Choose it for taste, not as a treatment.

Fluids to Limit or Avoid When Sick

Some popular beverages can actually work against your recovery efforts.

Alcohol: Alcohol can contribute to dehydration and may interact with medicines. It is best avoided while you are vomiting, have diarrhea, or feel dehydrated. If you are already reducing alcohol, Sober Tracker can help you keep that personal goal separate from illness care.

Caffeine: If coffee or strong tea worsens nausea or makes it harder to sleep, choose another drink for now. There is no universal one-cup rule for every illness.

Fruit juice and fizzy drinks during diarrhea: They can make diarrhea worse, so choose water or a pharmacist-recommended ORS instead. This matters especially for children.

Milk and other familiar drinks: If you tolerate them, they can contribute fluid. Choose what stays down and feels comfortable.

Hydration Strategies for Specific Illnesses

Different illnesses create different hydration challenges. Here's how to adapt your approach.

Cold and Upper Respiratory Infections

Choose water, tea, or broth at a temperature you find comfortable. Warm drinks may soothe a sore throat. Avoid steam inhalation over a bowl of hot water because of burn risk. Newcastle Hospitals NHS.

What to watch: Drink regularly if you can. A cold without vomiting, diarrhea, or heavy sweating does not require a preset increase. If your mouth is dry, urine becomes dark, or you urinate less often, increase fluids and reassess.

Best choices: Warm water with honey and lemon, herbal teas, clear broths, and room-temperature water.

Influenza (Flu)

Flu can bring fever and fatigue, making drinking feel like a chore. Keep a drink within reach and take small, frequent sips if larger amounts are uncomfortable.

What to watch: Replace fluids as tolerated and watch for dizziness, a dry mouth, or less frequent urination. Do not force a percentage increase or ignore a prescribed fluid restriction.

Best choices: Water and other drinks you tolerate are fine. Broth or tea can add variety. ORS is more relevant if you also have vomiting or diarrhea and are losing fluid and salts.

Stomach Flu (Gastroenteritis)

Vomiting and diarrhea can lead to dehydration, especially when you cannot keep drinks down. Start small and increase the amount as tolerated.

What to watch: No single liter target fits everyone. Notice how often you vomit or have diarrhea, whether fluids stay down, and whether urination decreases. Ask a pharmacist about ORS when losses are substantial.

Best strategy: Take small sips of water or a correctly mixed ORS, then gradually drink more as tolerated. If you or your child keep vomiting and cannot retain fluid, seek medical advice promptly.

Eating again: Eat when you feel able. Bland foods such as toast or rice may appeal, but there is no need to restrict yourself to a BRAT diet. Avoid foods that worsen your symptoms.

Fever

Fever may increase sweating. Offer fluids regularly and choose a temperature that feels comfortable.

What to watch: Pay attention to thirst, urine output, dizziness, and your ability to drink. Do not calculate an extra amount from the temperature reading.

Best choices: Water, tea, or broth may be easier to drink. ORS is useful when vomiting or diarrhea causes significant losses; fever alone does not automatically call for it.

Recognizing Dehydration During Illness

When you're sick, it's easy to become dehydrated without realizing it. Watch for these warning signs:

Early signs: Thirst, dark yellow urine, urinating less often, dry mouth, headache, or light-headedness can suggest dehydration.

Signs that need prompt advice: Persistent dizziness on standing, much less urine, unusual sleepiness, or a fast heart rate may mean dehydration needs urgent assessment.

Emergency signs: Confusion, difficulty waking, breathing difficulty, or cold or blotchy skin with dehydration symptoms calls for emergency care. Do not wait for a home fluid target to be reached.

Children and elderly adults are at higher risk for dehydration and may show signs more quickly. When in doubt, consult a healthcare provider.

Practical Tips for Staying Hydrated When You Don't Feel Like It

Loss of appetite and feeling unwell can make drinking difficult. These ideas may make small amounts easier to take.

Set Reminders: Use a water tracking app to send gentle reminders throughout the day. When you're foggy from illness, you may forget to drink otherwise.

Keep Fluids Visible: Place a water bottle, tea, or broth on your bedside table, couch, or wherever you're resting. Visual cues prompt drinking.

Use a Straw: Drinking through a straw requires less effort and can make consumption easier when you're exhausted.

Try Popsicles: Frozen fruit bars or homemade ice pops provide hydration in a form that may feel more appealing than drinking, especially with a sore throat.

Eat Hydrating Foods: If you can tolerate food, watermelon, cucumber, oranges, and soups all contribute to fluid intake.

Small Sips, Often: If you feel sick, start with small sips and gradually drink more as you can tolerate it. There is no required sip schedule.

Track Your Intake: A simple log can help you remember what you managed to drink. Water Tracker is a reminder and record, not a way to diagnose dehydration or decide whether medical care is needed.

Special Considerations

Children

Babies and children are at higher risk of dehydration. Continue breast or formula feeds, offering smaller feeds more often if needed. Ask a pharmacist about ORS for a child. Fewer wet nappies, few or no tears, or unusual drowsiness need medical advice. Do not dilute formula or give young children fruit juice or fizzy drinks for diarrhea.

Elderly Adults

Older adults are at higher risk of dehydration, especially when they rely on someone else for drinks or take medicines that affect fluid balance. Offer drinks regularly and notice changes in urination, dizziness, or alertness. Ask a clinician about existing fluid limits.

Pregnant or Nursing

If you are pregnant or breastfeeding, continue to drink regularly and ask your maternity team or clinician for advice if vomiting, diarrhea, or fever makes this difficult. Avoid generic targets that may not fit your situation.

Hydration for Recovery: After the Worst Is Over

Once acute symptoms settle, return toward your usual drinking pattern while responding to any ongoing losses.

Return to your usual pattern: As vomiting, diarrhea, or fever settles and you can eat and drink normally, resume your ordinary fluid routine. Continue to respond to thirst and any ongoing losses.

Keep drinks accessible: Rest and ordinary meals may be enough once acute losses end. No drink has been shown to rebuild immunity or shorten every illness.

Notice lingering symptoms: Fatigue has many causes after illness. If it persists or comes with signs of dehydration, get advice instead of assuming more water will solve it.

Resume normal activity gradually: As you return to work or exercise, drink according to thirst and conditions. Do not assume you need extra fluids once losses have ended.

When to Seek Medical Help

While most illnesses can be managed at home with rest and fluids, some situations require professional care:

Unable to keep fluids down: Seek prompt medical advice if you or your child keep vomiting and cannot retain fluids. Do not wait 24 hours to ask.

Dehydration signs: Get urgent advice for persistent dizziness on standing, much less urine, unusual drowsiness, or a fast heart rate. Confusion, difficulty waking, or breathing difficulty warrants emergency care.

Fever or illness concerns: Seek advice based on age, symptoms, duration, and any underlying condition. For a young infant with fever, contact a clinician promptly. Do not use this hydration article as a fever triage guide.

Symptoms worsen again: If you feel worse after improving or develop a new concerning symptom, get medical advice. This article cannot establish the cause.

Chronic Health Conditions: If you have diabetes, kidney disease, or other conditions affecting fluid balance, consult your doctor early in any illness.

Conclusion

During illness, the practical aim is to replace fluid you are losing with drinks you can keep down. Water is suitable for many mild illnesses. Vomiting or diarrhea may call for a pharmacist-recommended ORS.

Keep a drink within reach and take small sips if nausea makes drinking difficult. A reminder or intake log can help you notice your pattern, but symptoms and the ability to keep fluids down determine when to seek care.

If a child or older adult is becoming dehydrated, or if anyone has urgent warning signs, get medical advice promptly. No amount of tracking replaces an assessment.