Putting on a colostomy bag involves cleaning the skin around your stoma, measuring and cutting the wafer to fit, and pressing the system into place so it forms a secure seal. The whole process takes about 10 to 15 minutes once you get comfortable with it. Whether you’re doing this for the first time after surgery or troubleshooting a system that keeps lifting, the steps below cover everything from skin prep to final closure.
One-Piece vs. Two-Piece Systems
Before you start, it helps to know which type of pouching system you’re working with. A one-piece system combines the skin barrier (also called a wafer) and the pouch into a single unit. You peel, stick, and you’re done. The trade-off is that every time you change the pouch, the barrier comes off too, which means more contact with the skin around your stoma.
A two-piece system keeps the barrier and pouch separate. The barrier stays on your skin for several days, and the pouch snaps or clicks onto a flange built into the barrier. This lets you swap the pouch without disturbing the seal against your skin each time. Most people find two-piece systems easier on their skin over the long run, though one-piece systems feel simpler and sit flatter under clothing.
Gather Your Supplies
Lay everything out before you begin so you’re not reaching for items mid-process. You’ll need:
- Your pouching system (barrier, pouch, and flange if two-piece)
- Stoma measuring guide (a card with graduated circle cutouts)
- Curved scissors for cutting the wafer opening
- Warm water and a mild soap (avoid oil-based or moisturizing soaps, which leave residue that weakens adhesion)
- Clean washcloth or paper towels
- Skin barrier wipes or spray
- Stoma powder (if you have any irritated or weepy skin)
- Barrier rings or stoma paste (optional, for filling uneven skin contours)
- Pouch clip or closure
- A plastic bag for disposal of the old pouch
Remove the Old Pouch
Wash your hands thoroughly with soap and water, including between your fingers and under your nails. If you’re wearing a two-piece system, press gently on the skin around your stoma with one hand while peeling the barrier seal away with the other. Pull slowly and downward rather than ripping it off. If the adhesive resists, adhesive remover pads or wipes soften the bond without irritating the skin. For a one-piece system, the removal process is the same since the barrier and pouch come off together.
Save any reusable clips. Place the used pouch in a plastic bag, seal it, and throw it in the trash.
Clean and Inspect the Skin
Wash the skin around your stoma with warm water and a small amount of mild soap. A clean washcloth or paper towels work fine. Pat the area dry completely. Moisture is the most common reason a new barrier won’t stick properly, and damp skin under a sealed wafer can quickly become irritated skin.
While the skin is exposed, take a moment to look at it. Healthy peristomal skin should be pink or red, similar to the inside of your cheek. A small amount of bleeding from the stoma itself during cleaning is normal. If the stoma looks purple, black, or blue, contact your healthcare provider.
If you notice any raw, weepy, or irritated patches, sprinkle a light dusting of stoma powder on just those areas. Then gently dab (don’t wipe) a skin barrier wipe over the powder to seal it in place. This creates a dry, protected layer that adhesive can grip. Let everything air-dry for one to two minutes before moving on.
Measure and Cut the Wafer Opening
Your stoma can change size, especially during the first few months after surgery, so measure it each time you change the barrier. Slide the measuring guide over the stoma and find the circle that comes closest to the stoma’s edge without touching it. You want the opening to be snug, leaving as little exposed skin as possible between the stoma and the edge of the wafer. Exposed skin in that gap is vulnerable to contact with output, which is the leading cause of peristomal skin breakdown.
Trace the correct circle size onto the paper backing of your wafer. Use curved scissors to cut along the line, and run your finger over the cut edge to make sure it’s smooth. Rough or jagged edges can press into the stoma or create channels where output seeps underneath.
Prepare the Barrier for Application
If the skin around your stoma has creases, folds, or uneven contours, this is where barrier rings or stoma paste earn their keep. Barrier rings are flexible, moldable strips that you stretch, shape, and press around the wafer opening (on the adhesive side) or directly onto your skin to fill in dips and create a flatter surface. You can stack multiple rings if needed. Most people find rings easier and less messy than paste, though paste works for smaller gaps. Either option helps prevent output from tunneling under the seal.
If the area around your stoma sits flat against your body in all positions (standing, sitting, bending), a standard flat wafer is all you need. If your stoma sits at or below skin level, or the surrounding skin has persistent folds that pull the wafer away, a convex wafer may give you a better seal. Convex wafers have a slight dome shape that presses into the skin and stabilizes the area. Soft convex products tend to work better on firm skin, while firm convex products work better on soft, fleshy skin.
Attach the Pouching System
For a two-piece system, snap or click the pouch onto the barrier’s flange before you apply the barrier to your skin. Some people prefer to attach the pouch after the barrier is in place, but connecting them first lets you handle the whole unit at once and avoid pressing hard on your stoma area during the snap.
Peel the paper backing off the wafer. If you’re using stoma paste (rather than barrier rings), apply a thin bead around the hole in the wafer. Center the opening over your stoma and press the wafer onto your skin, starting at the stoma and smoothing outward. Hold it in place with gentle, steady pressure for at least 30 to 60 seconds. Body heat activates the adhesive, so pressing a warm washcloth over the wafer for a minute or two helps form a stronger bond.
For a one-piece system, the process is the same. Center the opening, press down, smooth outward, and hold.
Close the bottom of the pouch with the clip or Velcro closure. If your pouch came with cotton balls or gel packs designed to absorb moisture inside the pouch, place them in before sealing. Wash your hands again when you’re finished.
When to Empty and When to Change
Empty a drainable pouch when it’s one-third to one-half full. A pouch that gets heavier than that pulls on the wafer seal, which can break the adhesion and cause leaks. Sit on the toilet, point the tail of the pouch downward between your legs, unclip the bottom, and let it drain. Wipe the inside of the pouch tail clean before re-closing.
The skin barrier itself typically stays in place for three to five days, though some people get longer or shorter wear depending on their skin, activity level, and output consistency. Change the entire barrier if you notice the edges lifting, if you feel itching or burning underneath (a sign output may be reaching your skin), or if the barrier looks like it’s breaking down.
Troubleshooting a Seal That Won’t Hold
The most common reason a pouch won’t stick is moisture. Even a thin film of sweat, water, or output residue on the skin prevents the adhesive from bonding. Make sure the area is completely dry before application, and avoid applying the system right after a hot shower when your skin is still warm and slightly damp.
Body hair around the stoma can also lift the wafer edge. If you notice adhesion problems in hairy areas, carefully trim the hair short with scissors or an electric trimmer. Avoid shaving with a razor, which can cause irritation and ingrown hairs under the seal.
An opening cut too large exposes skin to output, which causes irritation, which causes moisture, which causes the seal to fail. It’s a cycle that worsens quickly. If you’re caught in it, re-measure your stoma, cut a tighter opening, use stoma powder and barrier wipes to dry and protect any damaged skin, and consider adding a barrier ring for extra protection while the skin heals.
Weight changes, scarring, and hernias around the stoma can all alter the contour of your skin over time. If a system that used to work well starts failing regularly, the issue may not be your technique. A wound and ostomy care nurse can reassess your setup and recommend a different wafer shape, convexity level, or accessory combination.