Why Do Babies Put Everything in Their Mouth?

Last Updated on May 22, 2026 by Jordyn Koveleski Gorman

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Why do babies put everything in their mouth? Put simply: development. Another common question that tends to come along with the first one is what do I do about it?

The answer to that question is simple, too. Let them!

You read that right. From a feeding specialist’s perspective, we want to encourage babies to put safe objects in their mouths. From the minute a baby is born, they begin exploring the world through their sensory system. One of the most important forms of babies’ sensory exploration is mouthing objects.

What is “mouthing”?

The mouth is the beginning of the digestive system, and it also plays a major role in the body’s senses. Taste, touch, and even smell are linked to the mouth. Mouthing is simply when a baby puts something in their mouth to explore (but not necessarily to eat).

Babies first begin by mouthing their own hands, typically as a hunger cue, which helps them quickly learn that the hands and the mouth can work together to help satisfy one of our most basic needs: hunger. Babies begin to transition from bringing their hands to mouth as a hunger cue to more exploratory purposes around 3-4 months.

It is also around this time where you will start to see them show interest in bringing toys and teethers to their mouths. This hand-to-mouth coordination is important for helping babies develop and learn how to bring food and utensils to their mouths when they later start solids.

Mouthing helps babies prepare for starting solids

Having an “organized,” or coordinated and regulated, sensory system is what helps babies prepare for starting solids. 

Through putting objects in their mouths, babies begin to explore various textures, sizes, and shapes that will help develop and organize their oral sensory systems. Think of all the textures and mouth sensations you experience when eating. In order to safely eat, chew, and swallow food, your sensory system had to learn and organize that information. 

Mouthing toys and objects is the first step and the safest way to begin preparing our mouths for eating. That’s right! From the minute you give your baby their first teether, you are already preparing them for their first bite of real food (even though that’s still a few months away).  

Additionally, littles who bring teethers and toys to their mouth for exploration are more likely to self-feed when in the high chair. Another reason to encourage oral exploration early on!

The sensory system is not the only thing that needs to practice to get ready for eating. The muscles in baby’s mouth, as well as their tongue, also need their fair share of safe exploration before being trusted to handle food.

Mouthing and chewing on chew toys, objects, and teethers helps your baby strengthen and coordinate their jaw muscles for chewing practice. It also helps the tongue move around to prepare for handling food inside the mouth. Some research even hypothesizes that mouthing occurs to prime a child’s immune system for pathogens! (1)

Mouthing helps regulate baby’s sensory system

Along with eating preparation, mouthing objects and teethers can also help to regulate baby’s sensory system. Having a “regulated” sensory system means that our brains are taking in all of the information our body is receiving through the nervous system (the senses) and using that information to help us feel more alert or calm based on the situation we are in. 

One of the first ways babies learn to regulate their sensory system is through their mouths by sucking. 

Sucking not only allows a baby to fulfill a hunger cue (sucking milk from a bottle or nipple), but also causes them to feel calm. Think about how sucking (either on a bottle, nipple, pacifier, or finger) typically helps a very young baby to calm down when they are upset. That is a baby regulating their sensory system.  

As babies grow and develop, they continue to seek sensory regulation through their mouth. That will naturally transition from sucking on a pacifier to mouthing and chewing on toys and teethers. This transition usually happens around 3-4 months when baby is exploring their hands and beginning to grasp objects to bring them to their mouth.

What toys are safe to go in my baby’s mouth?

Of course, we want to be sure that baby is putting safe, clean, and appropriate things in their mouths.

A general rule of thumb is to ensure teethers are bigger than your baby’s hand and that only part of it fits inside baby’s mouth. This is true of anything baby mouths—the entire object should not fit in their mouth. Luckily teethers are usually much bigger than a baby’s mouth!

Introducing teethers can start as early as 8–10 weeks. The graphic below highlights our favorites. See the full list here! Around 3 months+, you can begin offering toys like these to your little one, as their grasping skills refine.

When is “mouthing” no longer appropriate?

Little ones may continue to put objects in their mouth well into toddlerhood. Typically, after baby’s first birthday, there starts to be a drop in mouthing frequency. As teeth continue to come in, your little one may look to put toys and teethers in their mouth, but overall mouthing occurrences should minimize as your toddler approaches 2–3 years of age. (2)

What if my baby isn’t interested in teethers?

If your baby is about 3 months old not showing interest in teethers or not starting to mouth objects yet, that’s okay! They just might not be ready. It is important to keep offering though, as we know that babies who put items in their mouth or respond well to teethers, tend to better tolerate the textures of food when starting solids.

Here are some things you can try to engage their interest in teethers:

• Hang toys from a play gym or car seat to increase interest and to help make it easier for baby to get the toy/teether to their mouth.
• Hold teethers to their mouth to help them explore as their hands get better at grasping. Sometimes baby’s grip strength or hand-to-mouth coordination needs a bit more time to develop, and that’s perfectly fine!
• Whenever you can, give them an opportunity to grasp and try to hold, and in time they will get there!

Help your baby meet milestones through play!

It probably feels like your little one is growing so fast. As a mom of 3, I understand. You’re doing an amazing job, and your baby is so lucky to have you!

Meeting developmental milestones might seem overwhelming, but it doesn’t have to be! You can download our free Milestone Checklist for 0–36 months to check and see where your baby is right now!

Not sure how to help baby meet their milestones? Check out our Playbooks! More than 100 age-appropriate activities that help support development using only what you have at home!

Sources

1. Fessler DM, Abrams ET. Infant mouthing behavior: the immunocalibration hypothesis. Med Hypotheses. 2004;63(6):925-32. doi: 10.1016/j.mehy.2004.08.004. PMID: 15504558.
2. Tulve NS, Suggs JC, McCurdy T, Cohen Hubal EA, Moya J. Frequency of mouthing behavior in young children. J Expo Anal Environ Epidemiol. 2002 Jul;12(4):259-64. doi: 10.1038/sj.jea.7500225. PMID: 12087432.