In most cases, a colostomy bag that fits well shouldn’t cause a detectable smell. If you do notice a smell, there could be a few treatable causes.

A stoma is an opening made through your abdominal wall to allow urine or stool to pass through.

A colostomy is a stoma that connects your large intestines to a pouch called a colostomy bag.

Many people worry that their colostomy bag will release a noticeable odor to the people around them.

Most pouches contain a charcoal filter that reduces the smell of gas released from your gastrointestinal tract.

If you do notice an odor, it’s often a sign that your bag is leaking or that your colonoscopy bag doesn’t fit properly.

Let’s look at some of the reasons why a colostomy bag may cause an odor and how you can prevent it.

All modern devices have filters filled with charcoal to neutralize the smell. If somebody is standing next to you, they shouldn’t be able to smell the stool inside of your bag in the same way they can’t smell the stool inside other people’s bodies.

It’s not uncommon to experience a leak between your skin and your bag. Often the leak is under the flange. The flange is the adhesive baseplate that attaches a colostomy pouch to your body. The flange is attached to the pouch in a one-piece system and is separated in a two-piece pouch.

Even if you feel like you can smell your colostomy bag, there’s a good chance that others can’t. People tend to be more attuned to the smell of their own bodies than to the bodies of the people around them.

Your pouch may release an odor that’s noticeable to others if there’s a leak or if you eat foods that cause a lot of smelly gas that can’t be filtered.

Here are some reasons your colostomy bag may create an odor.


A leak is one of the most common reasons why a colostomy bag causes an odor. In the Ostomy Life Study 2019, researchers collected data from a self-reported questionnaire from more than 50,000 people with a stoma in 17 countries.

In the survey, 76% of respondents reported a leak under their baseplate at least once every month and 65% experienced a leak outside their baseplate or onto their clothes a least once in the last year.

Defective equipment

Products that are damaged or expired may not provide a sufficient seal to prevent leaking. It’s important to follow the care instructions for your supplies and check the expiration date before using them.


Certain foods such as sulfurous vegetables may cause you to produce smelly gas that isn’t completely filtered. These vegetables include:

  • onions
  • garlic
  • chives
  • leeks
  • shallows
  • Brussels sprouts

Other high-sulfur foods that may cause your gas to be smellier than usual include:

  • fish and meat
  • cheese
  • eggs

Everybody’s body is different, and you may find some foods not on this list also give you gas.

Foods that make your stool particularly thick can cause pancaking. Pancaking is when the inside of your pouch sticks together, and the stool doesn’t drop to the bottom. This can potentially block your filter or lead to a leak that causes an odor.

Learn more about the best foods to eat with a colostomy bag.

Here are some ways that you may be able to prevent your colostomy bag from smelling:

  • Change your pouch regularly and avoid overfilling your pouch. The frequency you need to change it depends on your type of pouch.
  • Make sure your skin barrier fits snugly.
  • Try keeping your pouch secure during exercise and physical activity. Wearing accessories that support your pouch may help.
  • Contact your medical team to help identify the cause of the odor.
  • Consider wearing loose-fitting clothing around your pouch to avoid pancaking.
  • Consider avoiding foods that cause thickening of your stool. You may also benefit from keeping a food log to help find which foods cause your stool to thicken or cause smelly gas.
  • Adding lavender oil to your colonoscopy bag may help manage the smell.

It’s a good idea to contact a doctor if you notice a persistent odor coming from your pouch. They can help you identify the cause and advise you on preventive strategies. They can also make sure that your equipment is fitting properly and check for potential complications that may cause a leak, such as stomal necrosis (tissue death around the stoma).

Here are some other frequently asked questions people have about colostomy bags and odors.

What foods make colostomy bags smell?

Foods that contain high amounts of sulfur, such as onions or garlic, may cause you to produce more smelly gas.

How often do you need to change an ostomy bag?

Ostomy bags come in several styles, including drainable pouches that remain on your body while you empty them or closed pouches. Typically, closed pouches are replaced after each use. Drainable pouches may need to be replaced every 2 or 3 days.

Your coloscopy bag shouldn’t cause a noticeable odor if it’s fitting properly. If an odor does develop, it may be a sign that your bag is leaking. It can also be a sign that your body is producing a higher-than-normal amount of smelly gas.

Your pouch may leak if it’s overfilled, doesn’t fit properly, or if the equipment is defective. A doctor can help you find the underlying cause.