A Foley is a flexible tube inserted through the urethra into the bladder to drain urine. It’s the most common type of indwelling urinary catheter used in hospitals, and it stays in place for hours, days, or sometimes weeks thanks to a small balloon inflated inside the bladder. If a doctor or nurse mentions “placing a Foley,” this is what they mean.
How a Foley Catheter Works
A Foley catheter has two internal channels running through a single tube. The larger channel drains urine from the bladder. The smaller channel connects to a tiny balloon near the tip. Once the catheter is guided into the bladder, a healthcare provider inflates that balloon with sterile water, which anchors the tube in place so it can’t slide out. Small holes cut near the tip allow urine to flow continuously into a collection bag.
The tube connects to one of two types of drainage bags. During the day, most people use a small leg bag strapped to the thigh or lower leg, which is discreet enough to hide under clothing. At night, you swap to a larger bedside bag that holds more urine so you can sleep without emptying it.
Why You Might Need One
The most straightforward reason is that you can’t urinate on your own. This can happen with acute urinary retention, bladder obstruction, or an enlarged prostate. But Foleys are also placed in many situations where monitoring or healing takes priority:
- Surgery: Procedures expected to last a long time, involve the urinary tract, or require tracking fluid balance often call for a temporary Foley. It’s typically removed in the recovery room.
- Critical illness: When precise measurement of urine output matters, such as in an ICU, a Foley gives providers real-time data on kidney function.
- Immobilization: Patients with spinal injuries, pelvic fractures, or other conditions requiring extended bed rest may need one because getting to a bathroom isn’t possible.
- Wound healing: Open wounds in the sacral or perineal area heal better when kept dry, so a catheter helps manage incontinence in those cases.
- End-of-life comfort: For patients in palliative care, a Foley can reduce the physical burden of toileting.
Sizes and Materials
Foley catheters are measured using the French scale, where the number equals the tube’s diameter in millimeters multiplied by three. A catheter with a 4.7 mm diameter, for example, is a 14 French. Most adult women use sizes between 12 and 16 French. Most adult men use between 14 and 18 French, though sizes up to 24 French exist. Pediatric sizes start as small as 5 or 6 French for infants.
The two main materials are latex and silicone. Latex is softer and less expensive, but some people have latex allergies, which rules it out. Silicone catheters are firmer and resist kinking more than 50% better than latex, making them the better choice when insertion is difficult. Silicone also tends to cause less irritation during longer use.
What Insertion Feels Like
A healthcare provider inserts a Foley using sterile technique to minimize infection risk. The area around the urethra is cleaned, and a lubricating gel (sometimes containing a numbing agent) is applied. The tube is then gently advanced through the urethra until urine begins to flow, confirming it has reached the bladder. At that point, the balloon is inflated. The whole process takes a few minutes.
You’ll likely feel pressure and a brief burning sensation during insertion. Once the catheter is in place, most people adjust to the feeling within a short time, though you may notice an intermittent urge to urinate. That sensation comes from the balloon pressing against the bladder wall and is normal.
Caring for a Foley at Home
If you’re sent home with a Foley, daily maintenance is straightforward but important. Clean around the catheter site every day. Wash your hands before and after handling any part of the system. When emptying the drainage bag, make sure the spout never touches the toilet or any container to avoid introducing bacteria.
You’ll switch between your leg bag and night bag twice a day: leg bag in the morning, night bag before bed. Clean both bags daily with a solution of white vinegar and water. Keep the drainage bag below the level of your bladder at all times so urine flows downward by gravity rather than backing up into the bladder.
Infection Risk
The biggest concern with any indwelling catheter is urinary tract infection. Bacteria can travel along the outside of the tube or through the drainage system into the bladder. The risk increases by about 3 to 7% per day for bacteria entering the bladder, translating to roughly a 0.3% chance of actual urinary tract infection for each day the catheter stays in place. That might sound small, but it adds up quickly over a week or two.
In intensive care units, infection rates run three to five times higher than in general hospital areas, reaching about 7.8 infections per 1,000 catheter days. In long-term care facilities, the rate averages around 3.2 per 1,000 catheter days. This is why healthcare providers aim to remove Foleys as early as safely possible.
Other Possible Complications
Infection isn’t the only issue. Urethral trauma can happen during insertion or if the catheter is accidentally pulled while the balloon is still inflated. Some people experience urine leaking around the catheter, which can signal a blockage or bladder spasm rather than a sizing problem. Over longer periods, mineral deposits can build up on the catheter (called encrustation), potentially forming bladder stones. Rarely, a piece of the balloon can break off during removal and need to be retrieved.
Incontinence after removal is common but usually temporary. The bladder and urethra need time to regain normal function, especially after prolonged catheterization.
How Removal Works
Removing a Foley is much simpler than placing one. The provider uses a syringe to deflate the balloon by withdrawing the sterile water, then gently slides the catheter out. You may feel brief discomfort or a pulling sensation, but the process takes only seconds. Mild burning during your first few trips to the bathroom afterward is normal and typically resolves within a day or two.
Occasionally, the balloon doesn’t deflate when it should. This can happen because of a faulty valve, a blocked inflation channel, or crystallization of the fluid inside the balloon. The first fix is usually cutting the valve mechanism on the external port, which often releases the fluid. If that doesn’t work, a urologist may need to intervene. With silicone catheters specifically, the deflated balloon can sometimes form a cuff that catches on the bladder neck, requiring extra care during extraction.