A baby with a fever needs extra fluids more than extra food. Fever increases your baby’s energy expenditure by roughly 11% for every degree Celsius (about 7% per degree Fahrenheit) of temperature rise, which means their body is burning through fluids faster than usual. Most babies naturally lose their appetite when sick, and that’s okay for a day or two. The priority is keeping them hydrated while offering easy-to-digest foods if they’re old enough for solids.
Fluids Come First
Dehydration is the biggest risk when a baby has a fever. Their small bodies lose water quickly through sweating and faster breathing, so replacing that fluid matters more than getting calories in. What you offer depends entirely on your baby’s age.
For babies under 6 months, breast milk or formula is the only fluid they need. Do not give plain water to a baby this young. Their kidneys can’t process it well, and it can dilute the sodium in their blood to dangerous levels. Instead, offer shorter, more frequent nursing sessions or smaller, more frequent bottles. A baby who normally eats every three hours might do better with smaller feeds every one to two hours.
For babies 6 to 12 months, breast milk or formula remains the main source of hydration. You can also offer small sips of water between feeds. An oral rehydration solution like Pedialyte is helpful if your baby is vomiting or has diarrhea alongside the fever, since it replaces lost electrolytes that plain water doesn’t. Avoid fruit juice entirely before 12 months.
For toddlers over 12 months, water, milk, oral rehydration solutions, and popsicles made from an oral rehydration solution all work well. Clear juices like apple juice are acceptable in small amounts at this age, but sugary drinks, sports drinks, flavored waters with added sugar, and soda should be avoided. These can actually pull more water into the gut and worsen dehydration.
How to Tell If Your Baby Is Getting Enough
Count wet diapers. For infants, fewer than six wet diapers in a 24-hour period is a sign of mild to moderate dehydration. Other early warning signs include a dry or sticky mouth, fewer tears when crying, and a sunken soft spot on top of the head. If your baby seems less playful than usual, that can also be an early indicator.
Start fluids slowly, especially if your baby has been vomiting. A few teaspoons every five to ten minutes is a better strategy than offering a full bottle, which may come right back up. Gradually increase the amount as your baby keeps fluids down.
What to Feed Babies on Solids
If your baby is 6 months or older and already eating solid foods, don’t worry if they refuse meals. A day or two of lighter eating won’t cause nutritional problems. When they are willing to eat, choose foods that are soft, bland, and high in water content.
Good options include:
- Applesauce: easy to swallow and contains extra liquid
- Mashed bananas: gentle on the stomach and a good source of potassium, which is lost during fever and sweating
- Broth-based soups: warm liquids that double as both food and hydration
- Soft cooked fruits: peaches, pears, or watermelon chunks (age-appropriate sizes) provide water along with natural sugars for energy
- Warm cereal: oatmeal or cream of wheat thinned with extra breast milk, formula, or water
- Yogurt: cooling, easy to eat, and provides protein (use pasteurized, plain varieties for babies under 12 months)
Avoid anything heavy, greasy, or high in fiber. A sick baby’s digestion is already working harder than usual, and rich foods can trigger nausea or loose stools. Skip unpasteurized dairy or juices, which carry a risk of harmful bacteria that a feverish baby is less equipped to fight off.
Don’t Force Feeding
It’s tempting to push food when your baby isn’t eating, but a sick baby’s reduced appetite is a normal part of the immune response. Their body is redirecting energy toward fighting the infection. Pressing food on a baby who isn’t interested can lead to vomiting, which worsens dehydration.
Instead, follow your baby’s cues. Offer food at regular intervals but let them decide how much to eat. Once the fever breaks, most babies bounce back to their normal appetite within a day or two. If your baby hasn’t eaten much during the illness, you may notice they’re hungrier than usual for a few days afterward as their body catches up.
When Reduced Appetite Becomes Concerning
A baby who is alert when awake, can be comforted when crying, and takes at least some fluids is generally handling the illness well, even if they’re eating less. The distinction that matters is between normal sleepiness and true lethargy. A sleepy sick baby still wakes up for feeds and responds to your voice or touch. A lethargic baby is hard to wake, doesn’t make eye contact, and seems limp or unresponsive even when awake.
Seek medical attention if your baby shows signs of moderate dehydration (no wet diaper in six or more hours, no tears, sunken soft spot), refuses all fluids for several hours, or appears lethargic rather than simply tired. For babies under 3 months, any fever of 100.4°F (38°C) or higher needs prompt medical evaluation regardless of how well they seem to be feeding.