Bet you never thought you’d be searching for why your baby is spitting up clear liquid when you signed up for parenthood.

Yes, this is another surprise stop on your child-rearing journey: Babies can sometimes spit up clear liquid instead of curdled breast milk or formula.

But not to worry, usually the reasons why are temporary and not a cause for concern.

So clear liquid is part of the package deal. But what is it and why does it happen? Several things could be at play here: saliva, spit-up from breast milk or formula, mucus, or even a combination of these. Let’s take a closer look.

Spit-up

Babies under a year old spit up — for some it’s often and a lot. Usually, spit-up is simply part and parcel of their maturing digestive system.

Your baby may do you the kindness of burping before they spit up. So listen up and stay prepared with burp cloth in hand.

After a burp, you may see a lot of spit up or simply a white, milky drool. Sometimes the spit up or drool could be clear. Sometimes this is just partially digested formula or breast milk combined with saliva.

Whether it is white or clear, a little spit-up or drool after a feed is normal.

Vomiting

Your baby has a ton of learning to do. Including learning not to gulp down milk too quickly, not to eat more than their tummy can hold in one sitting, and how to digest food.

During the first months, while they’re still learning, your baby may vomit. Here’s how you spot the difference between vomit and spit-up:

  • Vomit shoots out when the muscles around the stomach contract forcefully to push out the contents.
  • Vomit will probably have some clear stomach juices mixed into it. It may also look like curdled milk or miniature lumps of cottage cheese.

Unless the vomiting is happening frequently or accompanied by other symptoms, like a fever, it may just be part of the learning process. Yes, you’ll get used to this part of parenting too.

Teething

Your baby will probably cut their first teeth between 4 and 7 months old. While this milestone is a cause to celebrate, it may not be painless. Teething can sometimes cause discomfort and even pain.

Drooling plenty of clear saliva is your baby’s way of coping. Sometimes they may even spit up some excess drool.

You can help ease your baby’s discomfort by rubbing the sore gums with your finger or giving them a cool teething ring to bite on. You can also use bibs to help catch some excess saliva as it drips off their chin.

But there’s not much you can do to stop the excess drool, even if it makes them spit up — just know that it’s a temporary phase.

On the other hand, if the spit-up turns to vomit, it’s not just teething. You should consider whether your little one has other symptoms and consult with your doctor.

Illness

Babies and children get sick more often than adults because their immune system is developing. From about 6 months old, when the immunity you gave to your baby starts to fade, your little one will have to start building up their own immune system.

Heads up: This developing immune system means your baby may start to get colds. Since your baby hasn’t yet learned to blow their nose or cough up mucus, they’ll be swallowing a lot of the mucus, which might cause vomiting. This mucus can come up as a clear or cloudy liquid when they vomit.

If your baby is vomiting and has fever and diarrhea, you may notice that the vomit is clear. This happens when nothing is left in the stomach to throw up except for clear stomach secretions.

Speak with your pediatrician if your baby exhibits these symptoms to be sure that your little one gets the appropriate care.

A fever of 100.4°F (38°C) or higher in a baby who’s under 2 or 3 months old also warrants a call to the doctor. You should also call your doctor if your older baby, between 3 and 6 months, has a fever of 101°F (38.3°C) or higher.

No matter their age, a fever that persists for more than 5 days warrants a call to the doctor and likely a visit.

Reflux

Your doctor will call it gastroesophageal reflux (GER). Reflux happens when your baby regurgitates food from their stomach and spits up. More than two-thirds of babies will have reflux that causes spitting up as often as a few times a day.

As long as your baby is happy and gaining weight, GER isn’t a cause for concern. Typically, it peaks at 4 months of age and by the time your baby is a year old, chances are it will probably be a bad memory.

In rare cases, GER can signal something more serious like an allergy, a blockage in the digestive system, or gastroesophageal reflux disease (GERD). Yes that D makes all the difference.

With GERD, your baby may vomit, refuse to eat, not gain weight, and let you know he’s unhappy by crying. Your doctor may advise you to feed your baby smaller meals more frequently and to change formula or to cut out dairy if you’re breastfeeding. Sometimes medication or surgery will be needed.

Pyloric stenosis

This rare condition is named after the pyloric sphincter muscle that sits at the outlet to the stomach and it affects well under 1 percent of infants in the United States (more boys than girls).

Babies with this condition have a pyloric sphincter muscle that is thickened and narrow (stenosis). The narrowed pyloric channel restricts food in the stomach from entering the small intestine.

The stomach reacts by contracting vigorously to force the food through, but because the channel is so narrow, the food is vomited up with tremendous force. This projectile vomiting can reach several feet away!

You’ll see clear fluid or curdled milk. As the channel narrows more and more, projectile vomiting becomes more frequent. Despite the vomiting, your baby still feels hungry and will want to eat again… and again.

If your little one is affected, you’ll start to notice this type of vomiting when your baby is 2 to 3 weeks old, but it can start as late as 6 weeks old. Without nourishment, your baby can become dehydrated, weak, and lose weight.

Although pyloric stenosis is a serious condition, it can be easily righted with surgery. If you suspect this is the issue you should call the doctor right away to discuss your baby’s symptoms.

When they’re spitting up lots of clear liquid you may think that your baby needs water to avoid dehydration. However, you shouldn’t give water to babies under 6 months of age.

Drinking plenty of water every day may be good for you, but it definitely isn’t good for your baby. That’s because babies have tiny tummies (about the size of a walnut in the first week) and their kidneys are still developing.

If you fill your baby’s tummy with water, their hunger mechanism is dulled, and they may not get the nutrients they need. In addition, if your baby’s water intake is too high, there’s a risk of water intoxication.

Sounds far-fetched? Not really when you consider the size of that tiny tummy. Too much water will lower the concentration of electrolytes such as sodium in the blood. So hold the water until your baby is about 6 months old and stick to formula or breast milk.

Your medical team is there to help you with concerns as your child grows. Don’t hesitate to contact them to discuss any issues.

While much of the mess around spit-ups can be easily handled (with a rag and some patience), if you see that your baby has fever, seems listless, is dehydrated, or doesn’t appear to be putting on weight, contact your doctor.

When you’re wiping away another spit-up, you may be tempted to throw in that towel. But hold on… one day soon your baby’s digestive system will be working smoothly and the two of you will be ready to move on to the next stage of child rearing.