Ostomy Uncovered: Filters

Disclaimer: This information is based on my own research into this particular aspect of stoma care as well as some personal experience and should not be used as medical advice or a diagnostic tool. The suggestions given within are taken from sources laid out in the references header.  If you seek advice regarding the things you experience within your own disease, please contact your SCN  for medical advice.

If you are looking for the entire ‘Ostomy Uncovered‘ series, you can find them all here.

What is a Ostomy filter?

A filter is integrated into the stoma bag to help with the build up and release of gas from the output produced by the stoma.

Most of the modern stoma bags – usually a manufacturers drive line product range – will include a filter within the bag itself, so that odour and gas can be control without the user having to manually deal with this issue.

How do they work?

Filters are commonly made from charcoal or carbon which helps with the management of odour and ‘ballooning’ due to gas. A filter should pull out the gas from the pouch through the filter and neturalise the odour at the same time. However, some filters work ‘too well’ – meaning they pull too much air out of the pouch causing ‘pancaking’.

In both of these cases, filter stickers are a good way at attempting to solve these issues.

Filter stickers are provided in most boxes of ostomy bags. However, not all will come with stickers but you can use medical tape to cover the filter in these instances. And when products do come with stickers, they usually come with more than the bags in the box, so its always a good idea to keep the spare ones, just in case.

The stickers can be used threefold:

  1. Keeps the filter dry – A primary reason for using filter stickers; to keep the filter dry when the bag gets wet – from either bathing or swimming. A wet filter can clog and fail, leading to issues.
  2. Prevents ‘the vacuuming effect’ – for any of those who experience pancaking, the stickers can provide a stop on the flow of air from the bag through the filter, thus leaving air / gas in the pouch to lessen the effect of pancaking.
  3. Keeps the filter working and leak free – By covering the filter with a sticker, even partially, will ensure the filter continues to work. In most cases, this will mean that the filter does not become oversaturated with output and leak output through it.

All of the above uses are something that is done on a very individual basis. Due to multiple circumstances – ranging from the type of stoma a user has, how their digestive system reacts to certain food which produce gas and / or odour; all the way through to the type of bag they find most suitable – can have an effect. I can not stress how important it is to experiment within your own limits and with an experienced and trusted SCN.

Why are they important and how are they relevant?

Ostomy manufactuers have responded to their consumers concerns by looking into the technology behind filters and how to best solve both pancaking and ballooning with the primary core product – the stoma bag. What can be seen is the follow criteria of what is important to consumers in regards to the qualities a filter must do:

  • Increase the time to and minimise the incidents of ballooning, which can otherwise a) cause leakage under the baseplate, b) make bag indiscreet and c) reduce feeling of security.
  • Minimise the odour from the bag, which can otherwise a) cause embrassessment and b) reduce feeling of security.
  • Reduce the handling of bag by reducing the need for a) ventilation through the outlet of the coupling and b) excessive changing of bags.
  • Ensure a good night sleep!

It is a tall order and with the requirements above and the vast spectrum of users out there, producing a product which delivers is a process which takes years of research, consultation and testing.

Important information

Some of the below information is for solutions for pancaking and ballooning. A post about these two issues exclusively will be coming later in the summer.

  • If you find your bag’s filter failing at times, consider changing the pouch more frequently – changing once a day is advisable. Or try a two-piece system so you can keep the baseplate on but just remove the pouch; therefore you’ll have a fresh filter which should be more efficient.
  • If you have a problem with odour, it is likely to be diet related, but again this is individual. Some people with a colostomy report problems with odour after eating green vegetables and onions. For people with an ileostomy the culprit foods may be fish, eggs, onions and cheese. This is something that would be seen after having had your stoma for a while and after you’ve returned to a normal diet.
  • Of course, the efficiency and effectiveness of the filters are variable, and are not always appropriate for all types of stomas. In general, there needs to be external pressure on the pouch to help expel the gas through the filter. This can be come from either clothes or from gentle pressure with a hand.
  • The filters also tend to clog or fail with looser stool, causing some odor breakthrough or even tiny leaks of stool through the filter itself.


  • Trapping air inside the pouch can help. Before applying the pouch, apply a filter cover and once the release liner is removed, blow into the pouch to insert a pocket of air. Finally, apply the pouch.
  • Increase your fluid intake: Dehydration and not drinking enough fluid can result in larger quantities of water being reabsorbed by the intestine; this causes dry faeces, which tend to stick. This is more for colostomies than ileostomies as they will already had a looser formed stool.
  • If you are using a one-piece closed pouch and the above doesn’t help, consider trying a two-piece appliance, or an open pouch. De-vaccuuming the pouch through the coupling or open outlet on a regular basis, for example every time you pass urine, is also a good way to get used to helping the issue.


  • An option for releasing gas that does not require a charcoal filter is the Osto-EZ-Vent. This product is a simple disposable nipple valve that can be attached to any pouching system. The valve can be opened and closed repeatedly to allow for the easy release of gas. Further information about the product can be obtained through the Respond website here.
  • For people who wear two-piece appliances, gas can easily be released by β€œburping” the pouch. Slightly separate the pouch from the flange at the top of the appliance (complete removal of the pouch is not required) to allow the gas to escape. Once the pouch is empty, reattach the pouch to the baseplate.

My Experience

I first came across my filter when I took my first bath after surgery. I saw the black circle in my Sensura Mio bag more prominently than before, and panicked. My box of stoma bags came with a packet of 15 blue tabbed stickers – filter stickers – to prevent the filter from getting clogged from water.

It wasn’t unsure I was experiencing thick output that would not fall to the bottom of my pouch did I begin using the stickers with regular use. By covering the filter at all times, I control the amount of air that escapes from the pouch. Which means, if anything I balloon but this is something I can fix by emptying my bag, where as pancaking – where the output sticks to area directly around the stoma, sometimes seeping underneath and causing leaks – for me is more difficult. I choose to deal with ballooning over pancaking because I have an ileostomy which I empty more often, it just made more sense to my lifestyle.

I’ve done this for almost eighteen months and I hardly ever experiencing pancaking. I still experience leaks, don’t get it wrong, but this is usually down to incorrect fitting of my seal and / or bag which is human error and requires nothing more than me doing better next time. It also means, I don’t require any more supporting products to help me manage pancaking. – ie lubricating deodorant.

This is something I took the time to assess and see if it was suitable for me. I would encourage anyone to try this but only if you feel comfortable. It is a personal preference and something I find most suitable with Sensura Mio bags also.

How do you feel about your ostomy bag filter? Do you find it works? Do you prefer other bags filters?

Do you have any questions or queries? Or just want to share your own experiences? Leave me a reply or tweet me @sapphire20 or find my blog page on Facebook!


VeganOstomy – A Practical Guide to Ostomy Filter Stickers

Coloplast UK – Ostomy Self Assessment Tool: Filter Control

Coloplast US – Step 3: Managing a Filter

Oxford University Hospital – Common Concerns for People with a Stoma (pdf)

The Stolen Colon – Passing Gas and farting with a Stoma

Gastrointestinal Society – Bad Gut: Gas in Pouch


  • Kenneth Gladman

    04/10/2018 at 21:05

    My daughter is going to need a ostomy bag after finding some medical issues. I want to be sure and get as much information as possible on them. I like that you recommend deodorizers to make sure you are keeping yourself maintained.

  • G Marchio

    18/02/2019 at 06:13

    I use a mio sensura coloplast bag with a filter…odor pastes through the filter almost every day. I am so frustrated and embarrassed as I am a teacher and the stinky air tills the room at times. COLOPLAST tells me they have never heard of this happening but after reading reviews, I know it happens a lot. Solutions anyone?

    1. Admin

      18/02/2019 at 07:16

      Hi, I understand your frustration. Have you tried using the filter stickers provided in the box? Half covering the filter (underneath the split cover, the small black circle) might help some what. But if this persists, it might be you need a different bag with a filter that suits your output.

  • Ostomy Uncovered – How to Resize Your Baseplate •

    11/01/2021 at 16:28

    […] Ostomy Uncovered: Filters […]

  • Ostomy Glossary •

    28/02/2021 at 15:42

    […] Filter – Most modern stoma bags contain some sort of filter to absorb and release some of the odours and gas created by output. Bags with filters however can become blocked or saturated by output if it is particular loose or watery over a period of time. This can affect the effectiveness of the bag’s ability to control the smell. Some companies provide covers or stickers for them, for individuals to protect the filters from water when showering or bathing, or for those individuals to specifically control the amount of air in their bag. You can read more here. […]

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