What is a stoma appliance?
A stoma appliance is a medical device used to manage and care for a stoma, which is a surgically created opening in the body. It keeps the artificial bowel or bladder outlet securely closed, collects output hygienically, and protects the skin around the stoma. The key components of a stoma appliance are:
- Bag: collects stool or urine passing through the stoma.
- Skin barrier: keeps the bag securely in place and protects sensitive skin from irritating output.
- Outlet (for ileostomies and urostomies): allows liquid output to be drained.
- Filter: releases gas and helps prevent odour.
- Viewing window: makes it easier to position the bag and check on the stoma.
The right stoma appliance makes a real difference day to day — for greater confidence and comfort. Are you choosing your first stoma appliance? Feel free to check out our respective guide.
How does a stoma bag work?
Your stoma continuously or intermittently produces output (stool or urine). The stoma bag collects this and protects your skin and clothing. With drainable bags, you open the outlet at the bottom to empty into the toilet, leaving the baseplate undisturbed on the skin. With closed bags, the whole system is removed when needed or at set intervals. With urostomy bags, you empty the bag regularly via the tap.
A good seal between the skin and the baseplate is key to reliable security. Even a small gap can lead to leaks, which is why getting the right baseplate size matters so much.
Understanding your stoma type
The type of stoma you have (colostomy, ileostomy or urostomy) has a major influence on which stoma appliance is right for you. Each stoma type comes with its own requirements for the bag and, in some cases, the skin barrier material too.
Ileostomy
With an ileostomy, all or part of the small intestine (ileum) is removed or diverted. Output comes directly from the small intestine, bypassing the large intestine, which is normally responsible for absorbing water and thickening stool. As a result, output tends to be loose to soft and contains more liquid than with other stoma types. It also passes continuously and unpredictably, which is why most people empty the bag around 4–6 times a day, often overnight too.
Output from an ileostomy also still contains active digestive enzymes — normally used to break down nutrients in the gut — which can be quite harsh on the skin. This makes a reliable, well-fitting skin barrier essential. If the stoma is flat or retracted, a convex baseplate can help raise it further into the bag and improve the seal.
Ileostomies are managed with a drainable system, which can be emptied several times a day without changing the whole appliance. This is usually a two-piece system, with a baseplate that stays on the skin for several days while the bag is changed as needed.
Our recommendation for ileostomies: Since output places extra strain on the skin, it's worth choosing a bag made from breathable, skin-friendly material. The Silkura® ileostomy bag uses a silicone skin barrier that combines gentle adhesion with a secure seal, and lifts away comfortably at each change. The water-resistant material holds up well through showering, bathing and swimming, and the ultra-soft design includes a viewing window, filter and 460ml capacity. With frequent changes, silicone really shows its strengths — it comes away from the skin far more gently than most other materials.
Colostomy
With a colostomy, part of the large intestine is removed or diverted. Output still passes through part of the large intestine before reaching the stoma, where — much like in natural digestion — water is absorbed and the stool thickens. The result is usually semi-formed to firm, with a more predictable pattern than with other stoma types, often once or twice a day, similar to before surgery.
Because colostomy output contains fewer digestive enzymes and less liquid than an ileostomy, it's noticeably less irritating to the skin around the stoma.
A closed colostomy bag is typically used. The Silkura® colostomy bag offers extra skin protection here too, and free samples are available. If the stoma sits further along the colon, closer to the small intestine, output tends to be more liquid — in which case a drainable system may be a better fit.
Urostomy
With a urostomy, urine is diverted through the ureters and out via a stoma. The bladder is removed or bypassed, so urine flows continuously, day and night.
This calls for a dedicated urostomy bag with a tap or valve at the base. Using an extension tube, the bag can be connected to a leg bag or night bag — worn discreetly under clothing during the day, or attached to the bed at night — so you don't need to empty the urostomy bag itself as often.
Materials and features at a glance
Clear vs opaque stoma bag
Clear bags make it easy to keep an eye on the stoma — useful straight after surgery, when the stoma needs monitoring, or for anyone with limited eyesight. Most people prefer opaque bags, as they're more discreet and can feel more reassuring psychologically. Some bags offer the best of both: an opaque cover that can be folded back when needed to reveal a small viewing window, then closed again when discretion is the priority.
Stoma bag colours
Stoma bags now come in a range of colours: beige (a classic, low-key option that works under most clothing), white/off-white (subtle and modern), black (especially discreet under dark clothing), and patterned designs. This one really comes down to personal preference — choose whatever you feel most comfortable in.
Filters and gas management
Most modern stoma bags include a filter (usually at the top or side) that releases gas while keeping odour contained. Filter performance varies between manufacturers, so it's worth trying a few brands to see which works best for you.
Closed vs drainable stoma bags
Which system suits you best comes down to your stoma type and the nature of your output. With an ileostomy, continuous, loose output calls for a drainable bag. A urostomy needs a urostomy bag with a tap or valve. A colostomy with firm, predictable output is usually managed with a closed system — though if the stoma sits closer to the small intestine and output is more liquid, a drainable bag can work well here too.
Closed stoma bags
A closed system is removed and disposed of completely once full, or at set times. It's sealed at the bottom and can't be drained. This works well for colostomies with firm, predictable output, and for anyone who values simplicity and maximum discretion.
Closed bags are quite straightforward and discreet. Since the whole system is replaced at every change, it's worth considering skin-friendly materials like silicone or alginate to look after the skin through more frequent changes.
Drainable bags
A drainable bag has an opening at the bottom (usually with a clip or Velcro-style closure) that lets you empty the contents without changing the whole system. For ileostomies and urostomies, this is the standard solution given the volume and consistency of output. Drainable bags can also suit colostomies at times — for example, with diarrhoea or temporarily looser output.
The bag itself tends to last longer, usually only needing changing every 2–3 days. The trade-off is that emptying takes a bit more dexterity, and there's a slightly higher risk of small mishaps.
One-piece vs two-piece systems
There are several types of stoma appliance designed to suit different needs and preferences. Broadly speaking, these fall into two main systems: one-piece and two-piece.
One-piece system
With a one-piece system, the skin barrier and stoma bag are joined together as a single unit. This means both the baseplate and the bag are removed and replaced together at every change.
Advantages of one-piece systems:
- Simple to use
- Very discreet since the system sits flat against the skin and doesn't add much bulk under clothing
- Popular with people who are active in sport or who often wear close-fitting clothes
Worth knowing: Because the skin barrier is removed with every bag change, the skin is exposed to change more often. For frequent changes, skin-friendly materials like silicone or alginate can help protect the skin better.
Two-piece system
With a two-piece system, the baseplate and stoma bag are separate, connected securely via a fitting mechanism — such as a click-and-lock system. The baseplate typically stays on the skin for two to three days, while the bag can be changed as needed.
Advantages of two-piece systems:
- More flexible day to day, since the bag can be changed without removing the baseplate
- Different bag sizes can be used depending on the situation — for example, a larger bag overnight or a smaller one for sport or swimming
- Gentler on the skin, as the baseplate is removed less often.
- Minor leaks can often be sorted with a bag change alone, without needing to replace the whole appliance
Worth knowing: The connecting ring makes this system slightly bulkier than a one-piece appliance, which may be a touch more noticeable under close-fitting clothing. Many people find the audible click when connecting reassuring. At the same time, it's important to check that the bag and baseplate are properly connected to avoid leaks.
Sizes and variants of stoma bags
Standard bags: the most common choice — good capacity in a discreet size under clothing.
Maxi bags: Better for overnight use (with an extension tube for urostomies), for higher output, or when a change isn't possible for longer periods.
Midi bags: a middle ground between standard and mini sizes — ideal if standard feels too big or too small.
Mini bags and stoma caps: Mini bags are smaller than standard stoma bags. Originally developed for children, they're now also used by adults who prefer a more discreet appliance or who have lower output.
Stoma caps are very small, closed appliances suitable only for people with a colostomy. They're mainly used by those who manage their output through irrigation, or who only pass small amounts of mucus or stool. Stoma caps are best suited to short periods or special occasions — such as sport, swimming or intimate moments — rather than everyday, ongoing use.
Stoma bags: Baseplates and skin protection
The baseplate (also known as the skin barrier plate) sits directly on the skin around your stoma and is a crucial part of your stoma appliance.
It protects the skin from contact with stoma output, keeps the bag securely in place, and should match the size and shape of your stoma as closely as possible. Baseplates are available pre-cut or cut-to-fit. There are also mouldable skin barriers that flex to match the shape of the stoma, making the appliance easier to fit with little or no cutting needed; which is especially helpful for irregularly shaped stomas, where they can also improve the seal.
Baseplates are further divided into flat and convex types:
- Flat baseplates sit flush against the skin and generally suit stomas that protrude well above skin level on an even abdomen
- Convex baseplates curve outward. The gentle pressure this puts on the skin around the stoma can help push the stoma further out. They're often used when the stoma sits level with the skin or is retracted, or when skin folds make a secure seal harder to achieve, and can help reduce the risk of leaks and skin irritation
Which baseplate suits you best depends on the shape of your stoma, your abdomen, and your individual needs. A stoma care nurse can help you choose the right appliance. If you'd like to know more about stoma skin care, here's a guide for you.
Comparing skin barrier materials: what's right for you?
Every stoma appliance is as individual as the person wearing it, which is why choosing the right skin barrier material matters. Different materials offer different properties — for example, in terms of skin-friendliness, moisture management or flexibility. Together with the right system and baseplate, they help create an appliance that's secure, comfortable and tailored to your needs.
Hydrocolloid
The tried-and-tested standard in stoma care. Hydrocolloid offers reliable adhesion, protects the skin around the stoma, and keeps the appliance securely in place day to day. For many people, it's the first choice, having proven itself in practice for years.
Combiflange
A skin barrier built on two-layer hydrocolloid technology. The two bonded hydrocolloid layers improve moisture absorption and boost adhesion, while the flexible, tapered edges add extra comfort. Combiflange especially suits those who want extra-secure adhesion or who have a higher risk of leaks.
Silicone
A breathable skin barrier that combines gentle adhesion with a secure seal. Silicone moves naturally with the body and supports the skin's natural moisture balance, making it well suited to sensitive or compromised skin, and for anyone who needs to change their appliance frequently.
Alginate
A skin barrier containing a natural seaweed-derived ingredient. It can hold up to 1.5 times more moisture than standard hydrocolloid, supporting better moisture management. Alginate is particularly suited to moisture-related skin issues, sensitive or irritation-prone skin, and can help take pressure off the skin barrier.
Microskin
An especially thin, flexible skin barrier that moulds closely to the body's contours and moves with you. Its low profile means it adds very little bulk under clothing, for a discreet feel. At the same time, Microskin offers reliable, skin-friendly adhesion — ideal for active people or those with irregular body contours.
Gelatine-free
A hydrocolloid skin barrier made without gelatine or other animal-derived ingredients. This option suits anyone who avoids animal products for personal, religious or ethical reasons. It still offers reliable adhesion, stays flexible, and is designed with good skin tolerance in mind. All products are also latex-free.
How to find the right stoma bag for you
The right stoma appliance is as individual as the person wearing it. Alongside your stoma type, your lifestyle, your skin and your personal preferences all play a part.
1. Know your individual needs
Start by thinking about what you need your appliance to do. These questions can help:
- What type of stoma do you have?
- How often does output occur?
- What consistency and volume does it have?
- Are you very active at work or in sport?
- Do you travel often or swim regularly?
- Is a particularly discreet appliance important to you?
The better you understand your own needs, the easier it is to choose the right appliance.
2. Consider your skin
The skin around your stoma matters just as much. Sensitive or already irritated skin, scarring, skin folds or a retracted stoma can all affect which baseplate or skin barrier material suits you best. A well-fitted appliance helps prevent skin irritation and reduces the risk of leaks.
3. Try products in everyday life
Many manufacturers offer free samples — including us. Take advantage of this to try out different systems or skin barrier materials.
Test new products not just at home, but in the situations you'd actually encounter day to day — during sport, showering, sleeping or travelling. That's the best way to find out what really suits your lifestyle.
4. Find the best solution together
Always discuss any changes to your appliance with your stoma care nurse. Together, you can work out which system, baseplate and skin barrier material suit your individual situation best.
Give any new appliance a little time, too. It often takes a few days to get used to the feel and the handling. If your stoma or your lifestyle changes, a different appliance may become the better fit. Your stoma care isn't set in stone — it can evolve alongside your needs.
Ready to find your perfect bag? Order free samples from our range and try out different materials and variants, with no obligation. Our stoma care advisors are on hand to help you choose. Get in touch with us, or talk to your stoma care nurse about which Unora bag is right for you.
FAQ: Stoma bags
What's the best stoma bag?
There's no single "best" stoma bag. The type of bag depends first and foremost on your stoma type and the nature of your output. Beyond that, the right appliance for you depends on the system (one-piece or two-piece), the baseplate, the skin barrier material, and your individual needs. Speak to your stoma care nurse and try free samples to find the appliance that works for you.
What's the best colostomy bag on the market?
The best colostomy appliance is the one you barely have to think about day to day. It stay s securely in place, protects your skin, and gives you the freedom to get on with your day exactly as you'd like — whether that's at work, at the gym or in your free time.
Which colostomy bags are leak-proof?
Leaks rarely come down to the bag itself — they're usually the result of an appliance that isn't quite the right fit. Have your stoma measured regularly by a stoma care nurse to make sure the baseplate fits precisely. If your stoma is flat or retracted, a convex baseplate can help, while skin barrier paste or strips can help even out any unevenness. If leaks keep happening despite this, a different system or manufacturer might suit your stoma better.
How long does stoma surgery take?
Stoma surgery usually takes 1–3 hours, depending on how complex the procedure is. If the stoma is being formed due to cancer, inflammatory bowel disease or trauma, surgery may take longer, as the underlying condition is treated at the same time as the stoma is formed. Your medical team will talk you through the details of your individual procedure beforehand.
When's the best time to change your bag?
How often you need to change your stoma appliance depends on your stoma type, your system, and your individual needs. The following intervals are a general guide, based on the 2011 guideline on stoma care from the German Society for Stoma, Continence and Wound Care:
One-piece systems:
- Urostomy and ileostomy: at least once a day
- Colostomy: 1–3 times a day
Two-piece systems:
Baseplate:
- Urostomy and ileostomy: every 2–3 days
- Colostomy: every 2–4 days
Bag:
- Urostomy and ileostomy: at least once a day
- Colostomy: 1–3 times a day, or as needed