Colostomy guide · SIIL Ostomy
Colostomy Bag: The Complete Guide to Types, Changing and Everyday Life
Everything you need to know about a colostomy bag in one place: how it works, which type to choose, how to change it step by step, and how to live well with it day to day.
A colostomy bag (also called a colostomy pouch) is a soft, sealed pouch that sticks around your stoma and collects stool after colostomy surgery. Because the colon still absorbs water, output is usually soft to formed, so many people use a closed pouch changed once or twice a day, while others prefer a drainable pouch emptied when it is a third to half full. Bags come as one-piece or two-piece systems, flat or convex, with or without a filter. Change the wafer every 3 to 5 days, size the opening to your stoma, keep the skin clean and dry, and support the weight of a full pouch so it stays sealed.
What a colostomy bag is and how it works
A colostomy is an operation that brings a piece of the large intestine (the colon) through an opening in the abdomen. That opening is called a stoma. It has no nerve endings for pain, it is pink or red and moist, and it cannot be controlled like a muscle, so stool leaves the body whenever the bowel moves.
The colostomy bag is what makes this practical. It is a lightweight, odour-proof pouch that attaches to the skin around the stoma with a soft adhesive barrier, called a wafer or baseplate. It collects stool and gas, and the pouch is emptied or replaced as needed. Done well, it is invisible under clothes and does not stop you from working, travelling, exercising or swimming.
The stoma
The end of the colon, brought to the surface of the abdomen. It shrinks over the first 6 to 8 weeks.
The wafer
A skin-friendly adhesive barrier with a hole cut to your stoma size. It seals and protects the skin.
The pouch
A sealed bag that collects stool and gas, with a filter that releases gas and neutralises odour.
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Where your colostomy sits changes what comes out
The further along the colon your stoma is made, the more water the bowel has absorbed, so the firmer the output. Knowing your type helps you choose the right bag and routine.
A colostomy can also be an end colostomy (one opening, the lower bowel is removed or closed off) or a loop colostomy (a loop of bowel is brought up and opened, often temporary). It can be temporary and later reversed, or permanent.
| Type | Where it is | Typical output | Usual bag |
|---|---|---|---|
| Ascending | Right side, start of the colon | Liquid to pasty, frequent | Drainable, often like an ileostomy |
| Transverse | Upper abdomen | Soft to pasty, a few times a day | Drainable or closed |
| Descending | Left side | Soft to formed, once or twice a day | Closed or drainable |
| Sigmoid | Lower left abdomen | Formed stool, often once a day | Closed pouch, irrigation possible |
Types of colostomy bags
There are four choices to make: closed or drainable, one-piece or two-piece, flat or convex, and which size and colour. None is better than another. The right one is the one that stays sealed, keeps your skin calm and fits your routine.
| Option | What it is | Best for |
|---|---|---|
| Closed pouch | Sealed at the bottom, thrown away after use | Formed output, changed once or twice a day |
| Drainable pouch | Open at the bottom with a clip or velcro closure | Softer output, ascending or transverse colostomy |
| One-piece | Pouch and wafer joined together | Flat profile, simple routine |
| Two-piece | Wafer stays on, pouch clicks on and off | Sensitive skin, flexible routine |
| Flat wafer | Soft, flexible barrier | A stoma that stands out from the skin |
| Convex wafer | Barrier with a gentle curve | A flush or retracted stoma, or skin folds |
| Filter | A charcoal vent that releases gas | Reducing ballooning and odour |
| Opaque or transparent | Colour of the pouch film | Privacy or easy checking of the stoma |
How to choose the right colostomy bag
Start with your output
Formed stool suits a closed pouch. Softer or more frequent output suits a drainable one.
Measure your stoma
Use a measuring guide and cut the wafer opening about 3 mm larger than the stoma.
Match your skin and body
Flat or convex, one-piece or two-piece, depending on your skin, folds and stoma shape.
Ask for samples
Manufacturers and your stoma care nurse can send free samples. Try each for a few days.
Think about your day
Work, sport, travel and sleep all play a part. A smaller pouch for the gym or a bigger one for the night can both sit on one wafer.
How to change a colostomy bag, step by step
Choose a quiet time when your bowel is less active, often in the morning before eating. Set everything out first so you can work calmly.
Prepare
Wash your hands and lay out a new wafer and pouch, a measuring guide, scissors, wipes and a disposal bag.
Remove gently
Peel the old wafer away from the top down, pressing the skin back with your other hand.
Clean the skin
Use warm water and a soft cloth, no oily soaps. Pat the skin completely dry.
Check the stoma
It should be moist and pink to red. Look for redness, rash or broken skin around it.
Size and apply
Cut the wafer opening about 3 mm larger than the stoma, remove the backing and press it on from the bottom up.
Hold it in place
Keep your hand over the wafer for 1 to 2 minutes so body warmth sets the adhesive.
Close and dispose
Fit and close the pouch, and put the old one in a sealed bag in the bin. Never flush a pouch.
How often to change and empty a colostomy bag
Closed pouches are usually changed once or twice a day. Drainable pouches are emptied when they are a third to half full so the weight does not pull on the seal, and rinsed or wiped at the opening.
The wafer or one-piece system stays on for about 3 to 5 days, or sooner if it itches, burns or starts to lift at the edges. Never wait for a leak: change it at the first sign. For a longer routine, see how often to change and empty your ostomy pouch.
Output, diet and gas
A new colostomy often takes a few weeks to settle into a rhythm. After that most people eat nearly everything. Introduce new foods one at a time, chew well and keep fluids steady.
If output is too loose, starchy foods like white rice, pasta, banana and oatmeal help. If it is too firm, add fluids, soft fibre like oats, cooked vegetables and pears, and move more. Foods like beans, cabbage, onions, eggs, fish and fizzy drinks make more gas and smell for many people. Our free nutrition guide gives you a simple reference.
- Loose output: rice, pasta, banana, oatmeal, applesauce, smooth peanut butter.
- Firm or slow output: more fluid, oats, cooked vegetables, pears, prunes, a daily walk.
- Gas and smell: go easy on beans, cabbage, onions and fizzy drinks; use filtered pouches.
Managing odour and gas
A sealed colostomy bag does not smell when it is closed. Odour appears when you empty or change it, or when the seal leaks. Use a pouch with a filter, empty it in the toilet and flush before changing, and keep a small deodorising drop or spray in your kit.
If the bag balloons, the filter may be blocked or wet. Release gas gently at the toilet, and use a filter cover when showering or swimming. For more, read how to manage ostomy odor.
Showering, swimming, sleeping and exercise
Colostomy bags are designed for daily life. You can shower with or without the pouch, because water does not harm a stoma. Most people swim with the bag on, using a filter cover and a swimsuit with an inner pocket. At night, empty or change the bag before bed and sleep on your back or side as you prefer.
Exercise is encouraged. Choose support that holds the pouch flat and avoid heavy lifting right after surgery. See swimming with a stoma for a full checklist.
- Shower: with or without the bag; pat the skin dry afterwards.
- Swim: empty first, use a filter cover and swimwear with a pocket.
- Sleep: empty before bed; a soft cover keeps the plastic off your skin.
- Exercise: wear a belt or wrap so the pouch does not swing.
Clothes and support that make a colostomy bag disappear
The right layer makes a colostomy bag easy to forget. High-waisted ostomy underwear with an inner pocket holds the pouch flat against your belly and hides its outline. A soft ostomy wrap adds smooth, gentle support under fitted clothes. A belt designed for ostomy pouches supports the weight of a full bag and takes the pull off the adhesive, which is where most edge leaks begin.
A fabric bag cover hides the plastic and stops it rustling. For the pool or beach, choose ostomy swimwear with an inner pocket. If you play sport or have little ones who climb on you, a stoma guard protects the stoma from knocks and seatbelt pressure.
Common colostomy bag problems and quick fixes
| Problem | Likely cause | What to try |
|---|---|---|
| Leaks under the wafer | Opening too big, creases, wet skin | Re-measure, smooth creases, dry the skin well, add a belt for support |
| Sore or red skin | Output on the skin, adhesive removal | Smaller opening, barrier powder or film, switch to two-piece |
| Pancaking | Stool piles at the top of the pouch | A drop of lubricant inside, a little air in the bag, a different filter |
| Ballooning | Blocked filter or lots of gas | Fresh pouch with filter, release gas, use a filter cover |
| Bulge near the stoma | Possible parastomal hernia | Support underwear or belt, avoid heavy lifting, see your stoma care team |
| Stoma looks longer than usual | Possible prolapse | Lie down and gently ease it back, call your stoma care team |
Colostomy irrigation: an option for some people
Some people with a descending or sigmoid end colostomy use irrigation, a method that empties the bowel with lukewarm water, usually every 24 to 48 hours, so they wear only a small cap or mini pouch in between. It needs training from a stoma care nurse and is not suitable for everyone, but many people love the freedom it gives.
Frequently asked questions
How long does a colostomy bag last?
A closed pouch is usually changed once or twice a day. A drainable pouch is emptied when a third to half full, and the wafer or one-piece system stays on for about 3 to 5 days, or sooner if it leaks or irritates.
Does a colostomy bag smell?
A sealed bag with a working filter does not smell. Odour appears when emptying or changing the pouch, or when there is a leak. Filters, deodorising drops and changing at the first sign of leakage keep it under control.
Can you shower with a colostomy bag?
Yes. You can shower with the bag on or off. Water does not harm the stoma, and a filter cover or a quick-dry cloth keeps the pouch tidy.
Can you swim with a colostomy bag?
Yes. Empty the pouch first, use a filter cover and wear swimwear with an inner pocket or a high-waisted swimsuit. Modern pouches and wafers are made to cope with pools, the sea and hot tubs.
What is the difference between a closed and a drainable colostomy bag?
A closed pouch is sealed and thrown away after use, which suits formed stool. A drainable pouch opens at the bottom so you can empty it, which suits softer or more frequent output.
How do I stop a colostomy bag from leaking?
Cut the wafer opening about 3 mm larger than the stoma, dry the skin well, smooth creases, hold the wafer in place for a minute or two, empty the pouch before it is too full, and support its weight with a belt or high-waisted underwear.
What can't you eat with a colostomy?
Most people can eat nearly everything. Beans, cabbage, onions, fizzy drinks, fish and eggs make more gas and smell, and raw, stringy or very fibrous foods can cause trouble early on. Introduce new foods one at a time and chew well.
Can a colostomy be reversed?
A temporary colostomy, often a loop colostomy, can usually be reversed after the bowel has healed, typically after several months. A permanent colostomy cannot be reversed.
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