Dr. Brown Baby Bottles: Why They Leak & How To Stop It

Some of the main causes of leaks in Dr. Brown’s bottles are as follows:

  • Nipple flow level too slow Try going up one size.
  • Bottle is assembled incorrectlyCheck the alignment of parts carefully.
  • Heating bottle with the collar on tightlyLoosen or remove the collar before heating.
  • Shaking the bottleStir formula to mix, or use a travel cap when shaking.
  • Bottle was overheatedDo not warm the milk beyond 98° Fahrenheit.
  • Overfilled bottleDo not fill the bottle past the fill line.
  • Travel discs used for transporting Use a travel cap instead of travel discs or the bottle cap for traveling.
  • Worn partsCheck all parts often for damage, and replace them when needed.

Dr. Brown’s recommends these steps:

  • Fill your bottle to the desired amount, being careful not to overfill.
  • Snap the nipple into the nipple collar and place loosely on the bottle.
  • Warm the bottle per warming instructions.
  • Snap the reservoir onto the insert.
  • Remove the nipple and collar and place the reservoir in the bottle.
  • Place the nipple and collar over the vent system and tighten snugly.

I personally loved using Dr. Brown’s bottles with my babies, but when you don’t follow the directions and usage tips precisely, they will leak.

However, almost all leaks from Dr. Brown’s bottles can be fixed fairly easily with just a few adjustments. 

Why & When Dr. Brown Bottles May Leak

Leaks can occur due to unintentional misuse. These leaks may be noted during feeding, while warming, after shaking, and when traveling.

Leaking During Feeding

Dr. Brown’s previous bottle models MUST be used with the vent system or else the bottle will leak considerably.

They have made a new Options bottle that allows you to use the vent system if desired, but it is not essential if you choose not to use it.

A bottle might leak if the insert and tube are not connected well or if the nipple collar is not tightened enough.

Leaking can also occur if the nipple flow level is too slow.


Be sure all parts are fitted securely before feeding your baby.

Try increasing the nipple flow level by one size to prevent your baby from sucking hard enough to push air into the vent, which will cause leaking from the collar.

Leaking While Warming

Leaking while warming a bottle is pretty common. Pressure changes can cause leaks out of the collar. 


Remove the insert and vent, and put a storage travel cap over the bottle to shake it or warm it in hot water. 

Leaking After Shaking

The bottle is probably leaking after shaking because the vent is still in the bottle as you shake it. 


Remove all the parts and use a storage travel cap to mix the formula in the bottle.

When reassembling the bottle, make sure that the bottle cap and collar are on tightly. 

Leaking When Traveling

Because the vent in a Dr. Brown’s bottle is open, the bottle needs to be upright or else it will leak.


If traveling a short distance, place a travel disk over the vent and under the nipple, and then screw the nipple collar on tightly before adding the bottle cap.

If you no longer have travel disks for your bottles, you can find them on Amazon.

If you’re traveling for a longer time and cannot guarantee the bottle will remain upright, remove the entire vent system, nipple, and collar, and use a storage travel cap to protect the milk and prevent leaks. 

How To Prevent Leaks With Dr. Brown’s Bottles

Dr. Brown’s baby bottles are known for their innovative venting system that helps reduce colic, spit-up, burping, and gas.

However, to ensure that they work properly and do not leak, it’s important to follow some specific steps:

  • Check the Vent System: Before each use, make sure the vent system is properly assembled. This system consists of several parts, including the vent insert, vent reservoir, and vent tube. Inspect them for any damage or wear.
  • Assemble Properly: Assemble the bottle according to the manufacturer’s instructions. Ensure that each part fits snugly and is in the correct position. Any misalignment can cause leaks.
  • Tighten the Collar: Once you’ve filled the bottle with milk or formula, make sure to screw the collar on tightly. This is crucial in preventing leaks.
  • Avoid Overfilling: Do not fill the bottle above the indicated fill line. Overfilling can put excess pressure on the vent system, potentially causing leaks.
  • Check for Wear and Tear: Regularly inspect the bottle, collar, and vent system for any signs of wear, cracks, or damage. If you notice any, replace the damaged parts immediately.
  • Use Correct Nipple Flow: Ensure that you’re using the correct nipple for your baby’s age and feeding needs. Using a nipple with a faster flow than necessary can lead to excess milk entering the vent system, causing leaks.
  • Hold the Bottle Correctly: When feeding your baby, make sure the bottle is held at the correct angle. This often means keeping the vent system in an upward position that allows air to flow properly.
  • Avoid Shaking Vigorously: Avoid shaking the bottle too vigorously. If you need to mix formula, gently swirl the bottle instead. Vigorous shaking can cause the vent system to malfunction.
  • Avoid Overheating: Overheating causes the air inside the bottle to expand, thus forcing milk into the vent.
  • Clean Thoroughly: Clean all parts of the bottle thoroughly after each use. Pay special attention to the vent system to ensure it’s free from any blockages or residue.
  • Check for Warping: Over time, plastic bottles can warp due to high heat or aggressive cleaning. If you notice any warping, it’s best to replace the affected parts.
  • Replace Damaged Parts: If you notice any parts of the bottle or vent system that are damaged, replace them immediately. Using compromised components can lead to leaks.

Dr. Brown’s Bottle: Milk in Vent

It’s important to address milk entering the vent promptly as it can affect the bottle’s effectiveness in reducing colic and gas.

Here are some potential reasons for milk in the vent and how to prevent it:

1. Overfilling the Bottle

If you fill the bottle above the indicated fill line, it can lead to excess milk entering the vent system.

This can overwhelm the venting mechanism, causing milk to flow into the vent.

Prevention: Always fill the bottle to the recommended level, which is usually indicated on the bottle itself.

2. Improper Assembly

If the vent system is not properly assembled or any of its components are misaligned, it can lead to leaks. This can allow milk to enter the vent.

Prevention: Ensure that you follow the manufacturer’s instructions for assembling the bottle, and check that all parts fit snugly and are in the correct position.

3. Incorrect Nipple Flow

Using a nipple with a flow rate that is too fast for your baby’s feeding stage can lead to excess milk entering the vent system. 

Prevention: Use the appropriate nipple flow for your baby’s age and feeding needs.

4. Vigorous Shaking

Shaking the bottle too vigorously can disrupt the vent system and cause milk to enter it.

Prevention: Instead of shaking, gently swirl the bottle to mix the formula or stir it with a spoon.

5. Warped or Damaged Parts

If any parts of the bottle or vent system are warped, cracked, or damaged, they may not function properly, leading to milk entering the vent system.

Prevention: Regularly inspect all parts for wear and tear, and replace any damaged components immediately.

6. Feeding Position

Holding the bottle at the incorrect angle during feeding can cause milk to flow into the vent.

Prevention: Hold the bottle at the recommended angle, typically with the vent system in an upward position.

7. Air Bubbles in Formula

If the formula has air bubbles, they can travel through the vent system and push milk into the vent.

Prevention: Mix the formula gently to minimize the presence of air bubbles.

Dr. Brown Bottle Parts & Design

Dr. Brown’s bottles have a unique insert that can be put into the bottle to help circulate air better and prevent gas for your baby.

The insert consists of two parts: a vent insert and a reservoir tube that looks like a straw.

The reservoir tube has a reservoir bulb at the top.

The insert and reservoir tube need to be pressed together very tightly in order for the vent to work properly.

The insert is held in place by a nipple collar that secures the nipple to the vent.

The nipple collar directs air from the vent to the bottom of the bottle, completely bypassing the milk so that less air is ingested during feeding.

Dr. Brown’s bottles also come with a travel disc to prevent spills when traveling and a cap to cover the nipple to keep it sanitized. 

How To Use Dr. Brown’s Bottles

Dr. Brown’s bottles have a couple more steps for assembly than most of their competitors. To assemble a Dr. Brown’s bottle:

  1. Set the bottle upright on a solid surface, and fill with milk or formula. Do not overfill.
  2. Place the nipple inside the nipple collar, making sure it is sealed all the way around. 
  3. Put the nipple and collar on the bottle without fully tightening, and warm according to the instructions.
  4. Press the reservoir onto the insert. 
  5. Remove the nipple and collar. Insert the two-part vent system.
  6. Screw the nipple collar over the vent insert. Tighten.
  7. Always check the milk temperature before feeding your baby. 

How To Warm Dr. Brown’s Bottles

Dr. Brown’s bottles can be warmed in a variety of ways. Remember to always remove the vent system to help prevent leaks.

You can warm a Dr. Brown’s bottle on the stove in hot water.

  • Heat water in a pot that is about equal to the amount of milk in the bottle.
  • Allow the water to warm to about 98 degrees Fahrenheit before adding the bottle to warm.

You can also warm a bottle by running it under hot water from your faucet.

Bottle warmers are another option (I use my Baby’s Brew Portable Warmer all the time and LOVE it!). 

Always test the temperature of the milk on the inside of your wrist before feeding your baby.

Are Dr. Brown’s Bottles Microwave Safe? 

The American Academy of Pediatrics warns very explicitly against microwaving any bottle.

The outside of the bottle may feel barely warm to the touch while the milk inside could be scalding.

Microwaves heat unevenly, which could result in injury to your baby.

Research indicates that the microwave can change the composition and nutrients in breast milk. 

How To Clean Dr. Brown’s Bottles

Dr. Brown bottles are all top-rack dishwasher safe. They can also be washed by hand with hot water and soap.

If cleaning by hand, use the brush that comes in your bottle packaging to clean out the reservoir straw correctly.

Sterilize the clean bottle according to your desired method.

How Often To Sterilize Dr. Brown’s Bottles

The Centers for Disease Control recommends sterilizing bottles after every use if your baby is under 2 months old or has a weakened immune system.

Dr. Brown’s recommends sterilizing bottles in the following situations:

  • If your baby is sick.
  • If the bottle has come in contact with a dirty surface.
  • If you have traveled with the bottle.
  • If the bottle has had breastmilk or formula in it longer than the recommended time. 

How To Sterilize Dr. Brown’s Bottles

To sterilize Dr. Brown’s bottles, wash them with hot water and soap, and then place them in a microwave sterilizer or a sterilizing machine.

Using steam to clean bottles is the best way to sterilize them.

Dishwashers that use high heat and steam to clean could be used to sterilize a bottle.

When To Replace Bottle Nipples

Nipples should be checked every month or so. If any cracks are present, the nipples should be replaced immediately.

Dr. Brown’s recommends changing nipples out every 3 months or so to keep them in good working order. 

Dr. Brown Bottles Without Vent

You can remove the vent from your baby’s bottles when you feel that feeding habits have improved to a level you are all comfortable with.

Dr. Brown’s advises that it’s okay for vents to be removed when babies are able to sit up on their own, when they have started eating solid foods, and when they aren’t showing any signs of colic, gassiness, or reflux.

These will happen at different ages for different babies, but usually, the vent can be removed at 6-8 months.

The advantages to removing the vent are that babies can drink a bit faster and there are fewer parts to clean after each feeding.

Dr. Brown’s Bottles Blue vs. Green

Dr. Brown’s has two different kinds of bottles: one is green and one is blue.

The blue bottle is not able to be used without a vent. If you use it without a vent, it will leak.

The bottles with the green vents can be used with or without the vent.

Once a baby is no longer colicky or gassy, the green vent can be removed without fear of leaking.