Should I drink a lot of water if I have an infection?

October 9, 2025 •

4 min read

The human body is made up of approximately 60% water, and staying hydrated is critical for nearly every bodily function. So, should I drink a lot of water if I have an infection? Yes, increasing your fluid intake is often necessary to support your immune system and combat dehydration caused by common illness symptoms.

Quick Summary

When battling an infection, proper hydration is key to supporting your body's immune response and preventing complications like dehydration from fever or fluid loss. While increasing fluid intake is important, it's crucial to find the right balance, as excessive water consumption can dilute electrolytes, a condition known as hyponatremia.

Key Points

Increase Fluid Intake: During an infection, fever, sweating, and other symptoms cause increased fluid loss, making it necessary to drink more than usual to prevent dehydration.
Balance is Key: While dehydration is a significant risk, drinking excessively large amounts of plain water can dilute blood sodium, potentially causing dangerous overhydration (hyponatremia).
Choose the Right Fluids: Prioritize plain water, oral rehydration solutions (especially with vomiting or diarrhea), broths, and herbal teas. Avoid caffeinated and high-sugar drinks.
Monitor Your Urine: The easiest indicator of proper hydration is pale yellow or clear urine. Dark yellow urine signals a need for more fluids.
Support Your Immune System: Proper hydration is essential for immune cells to circulate effectively, regulate body temperature, and flush toxins from the body to aid recovery.
Recognize Warning Signs: Know the symptoms of both dehydration (fatigue, dark urine) and overhydration (nausea, headache, confusion) to act accordingly.

The Importance of Hydration During an Infection

When you are sick, especially with an infection, your body loses fluids faster than usual. Fever increases sweating, while symptoms like vomiting or diarrhea expel significant amounts of fluid and electrolytes. This fluid loss can hinder your body's ability to fight off the infection effectively. Maintaining proper hydration is vital for several reasons:

Supports the Immune System: Water is a major component of lymph, the fluid that transports immune cells throughout your body. Staying hydrated helps your immune system operate at peak efficiency, allowing white blood cells to reach the infection site faster.
Regulates Body Temperature: A fever is a natural immune response, but without adequate fluid intake, your body can struggle to regulate its temperature, potentially leading to overheating. Proper hydration helps your body maintain a stable core temperature.
Flushes Out Toxins: Your kidneys and liver rely on sufficient fluid levels to filter and flush out waste products and toxins from your body. Hydration ensures these detoxification processes are not strained during an infection.
Keeps Mucous Membranes Moist: When battling a respiratory infection, staying hydrated helps thin mucus, making it easier to expel. It also keeps the mucous membranes in your nose and throat moist, which is essential for protecting against viral invaders and soothing irritation.

The Risks of Overhydration (Water Intoxication)

While drinking water is crucial, excessive intake can lead to a dangerous condition called hyponatremia, or water intoxication. This occurs when too much water dilutes the amount of sodium in your blood, causing your body's cells to swell.

Symptoms of Overhydration

Nausea and vomiting
Headaches
Confusion or irritability
Muscle weakness, spasms, or cramps
Bloating
In severe cases, seizures, coma, or even death.

For most people with healthy kidneys, it is difficult to drink enough water to cause hyponatremia. However, people with certain medical conditions, such as kidney disease, or those experiencing extreme illness with prolonged vomiting or diarrhea are more susceptible. It is always best to let your thirst guide you and sip fluids steadily rather than chugging large amounts at once.

What to Drink When You Have an Infection

Recommended Fluids

Water: Plain water is always the best choice for everyday hydration and should be your primary fluid source when sick.
Oral Rehydration Solutions (ORS): If you are experiencing vomiting or diarrhea, a balanced ORS (like Pedialyte) is more effective than plain water or sports drinks for replenishing lost electrolytes and fluids. The World Health Organization recommends ORS for mild to moderate dehydration.
Herbal Tea: Warm herbal tea can be soothing for a sore throat and help with congestion. Just be sure to avoid caffeinated teas, which can be dehydrating.
Broth or Soup: Broths are an excellent way to rehydrate and replenish sodium and other electrolytes, especially when you have a sore throat or lack an appetite. Warm chicken soup has even been shown to have an anti-inflammatory effect.
Fruit and Juice (in moderation): Fruits and diluted fruit juices contain water, vitamins, and minerals. However, be cautious with pure juice, as high sugar content can worsen diarrhea and stomach upset.

Fluids to Avoid

Caffeinated Beverages: Coffee, soda, and energy drinks are diuretics, meaning they cause your body to excrete more fluid. Avoid these while sick to prevent dehydration.
Alcohol: Alcohol is highly dehydrating and impairs the immune system's ability to fight infections. It should be avoided completely.
Sugary Drinks: High-sugar drinks like many sports drinks and juices can be too concentrated and pull water into the intestines, potentially worsening diarrhea.

How to Tell if You're Hydrated Enough

One of the easiest ways to monitor your hydration level is by observing the color of your urine. When you are properly hydrated, your urine should be pale yellow and clear. If your urine is dark yellow or amber, it is a clear sign that you need to drink more fluids. Other signs of dehydration include:

Dry mouth, lips, or skin
Fatigue or dizziness
Headaches
Less frequent urination
Feeling excessively thirsty

If you experience any severe symptoms of dehydration, such as confusion, fainting, or a rapid heart rate, seek immediate medical attention.

Comparison Table: Hydration and Overhydration During an Infection


Feature	Adequate Hydration During Infection	Overhydration During Infection
Goal	Replenish fluids lost from fever, sweating, vomiting, or diarrhea.	Drinking far more than your body needs, diluting electrolytes.
Recommended Fluids	Water, oral rehydration solutions, broth, herbal tea.	Excessive amounts of water, especially plain water.
Electrolyte Balance	Maintains a healthy balance of sodium, potassium, and other minerals.	Causes dangerously low sodium levels (hyponatremia).
Urine Color	Pale yellow or clear, with regular urination.	Almost entirely clear, with frequent urination.
Physical Symptoms	Headache relief, reduced fatigue, moist mucous membranes.	Nausea, vomiting, muscle cramps, headache, confusion.
Overall Effect	Supports immune function, aids in temperature regulation, and promotes recovery.	Can impair cellular function, lead to brain swelling, and cause life-threatening complications.

Conclusion

When dealing with an infection, the answer to the question "Should I drink a lot of water?" is yes, but with a critical caveat: focus on balanced, steady fluid intake rather than extreme consumption. Your body requires extra fluids to replace those lost through fever, sweating, and other symptoms. By choosing beneficial fluids like water, oral rehydration solutions, and broths, you can effectively support your immune system and promote a faster recovery. Monitor your urine color and listen to your body's signals to avoid both dehydration and the less common, but serious, risk of overhydration. Always consult a healthcare provider if you have concerns about your hydration levels or specific symptoms during an illness. For more health tips, you can refer to information from trusted organizations like the Mayo Clinic.

Frequently Asked Questions

The initial signs of dehydration include increased thirst, dark yellow urine with a strong smell, feeling tired or dizzy, and a dry mouth or lips.

It is better to sip water steadily throughout the day rather than chugging large amounts at once. This helps your body absorb the fluid more effectively and is less likely to cause nausea, especially when dealing with a sensitive stomach.

You should consider an electrolyte solution if you are experiencing symptoms like vomiting or diarrhea, which cause significant fluid and mineral loss. Oral rehydration solutions are designed to replace these lost electrolytes and fluid balance more effectively than plain water or sugary sports drinks.

It's best to avoid caffeinated drinks like coffee and black tea when sick, as they are diuretics and can contribute to dehydration. Stick to water, broth, or caffeine-free herbal teas to stay properly hydrated.

Signs of overhydration can include clear urine, frequent urination, nausea, headache, and muscle cramps. If you suspect overhydration, you should stop drinking fluids and consult a doctor, as severe cases can be a medical emergency.

Yes, a fever increases your body temperature, leading to more fluid loss through sweating. You should increase your fluid intake when you have a fever to help regulate your body temperature and prevent dehydration.

When you feel nauseous, try sipping on small amounts of bland fluids like water, herbal teas with ginger, or broths. Popsicles and ice chips can also be good options to get fluids and soothe your stomach.