What Is a Foley Catheter? A Plain-Language Guide

Last verified: October 6, 2026. A Foley catheter is a thin, flexible tube that sits inside the bladder to drain urine continuously into a collection bag. It is the most familiar kind of indwelling urinary catheter, and it is recognizable by one design feature: a small balloon near the tip that is inflated once the catheter is in place so it cannot slip back out. This guide explains what a Foley catheter is, why it exists, its main types, how it differs from other catheters, and what research administrators, procurement staff, and lab or clinic managers should know about it.

This page is general information, not clinical or safety training. Always follow your institution’s procedures and the manufacturer’s instructions for use.

What Is a Foley Catheter?

A Foley catheter is a sterile, hollow tube, usually made of silicone or latex-based material, that is placed through the urethra into the bladder. It has two internal channels. One lets urine flow out of the bladder and into a drainage bag. The other connects to a small port outside the body and leads to a balloon near the tip. After the tip reaches the bladder, the balloon is filled with sterile fluid, which holds the catheter in place until the balloon is deliberately emptied for removal. The tube is described as “indwelling” because it stays in place for a period of time rather than being inserted and removed straight away.

The Problem a Foley Catheter Solves

The bladder normally stores urine and empties on demand. Several situations interfere with that. A patient may be under anesthesia and unable to urinate. Swelling, a blockage, or nerve damage may prevent the bladder from emptying. A critically ill patient may need urine output measured precisely over hours because it is a clue to how well the kidneys and circulation are working. Some patients cannot manage skin care or mobility in a way that is compatible with leakage. A Foley catheter handles all of these by providing a reliable, continuous path for urine to leave the body, and by making the volume measurable.

It also carries risk. Any tube that bridges the outside world and the bladder can introduce bacteria, which is why catheter-associated urinary tract infection is a major focus of hospital quality programs. You can read more in the guide to the CAUTI prevention bundle. Because of that, good practice generally treats a Foley catheter as something to use only when needed and to remove as soon as it is no longer needed.

Parts of a Foley Catheter System

• The catheter tube — the flexible shaft that is inserted. Its outside diameter is described using a French size, where a larger number means a wider tube.
• Drainage eyes — openings near the tip that let urine enter the drainage channel.
• The retention balloon — inflated with sterile fluid to anchor the catheter in the bladder.
• The balloon inflation port — a small valve where the fluid is added or removed.
• The drainage port and connector — the outer end that joins the tube to a collection system.
• The drainage bag and tubing — a closed system that collects urine, often with a valve at the bottom for emptying and a port for sampling.
• A securement device — a strap or adhesive fixture that keeps the tube from pulling, which reduces discomfort and injury.

Who Uses a Foley Catheter

Foley catheters are placed and managed by trained clinical staff, typically nurses, physicians, and other qualified practitioners, using sterile technique. They are common in hospitals, particularly in operating rooms and intensive care units, and are also used in long-term care and, with training, in home care. Urology clinics use them frequently. Veterinary medicine uses analogous catheters in animals, and some research settings use catheters in animal models, although the sizes and designs differ.

Types of Foley Catheters

By number of channels

• Two-way catheters have one channel for drainage and one for the balloon. This is the standard design.
• Three-way catheters add a third channel that allows fluid to be irrigated into and out of the bladder, which is used in specific situations such as ongoing bleeding. They are larger and are chosen only when that extra function is needed.

By material and coating

• Latex-based catheters are flexible and economical, but latex allergy limits their use for some patients.
• Silicone catheters are latex-free and are often preferred when allergy is a concern or for longer use.
• Coated catheters have surface treatments intended to reduce friction or irritation. Some are marketed as antimicrobial. Coating claims differ by product, so they should be evaluated against manufacturer documentation and institutional policy.

By tip and size

Catheters come in a range of French sizes and in a few tip shapes, and in adult and pediatric versions. Balloon volume also varies. Selecting the right combination is a clinical decision. For a broader look at the family of products, see the urinary catheter types and selection guide.

Complete kits

Many suppliers sell Foley catheters as part of an insertion tray that includes gloves, drapes, antiseptic, a prefilled syringe, and a drainage bag. Trays reduce the chance that something is missing at the bedside and help standardize technique, but they cost more than buying components separately.

How a Foley Catheter Differs from Other Catheters

• Foley vs. straight (intermittent) catheter — a straight catheter has no balloon. It is inserted to drain the bladder and then removed right away, and some people use one on a schedule to empty their own bladder. A Foley is designed to stay.
• Foley vs. external (condom-style) catheter — an external catheter fits over the outside of the body and does not enter the urethra, so it avoids some of the infection risk of an indwelling tube, but it is only suitable for some patients.
• Foley vs. suprapubic catheter — a suprapubic catheter enters the bladder through a small opening in the lower abdomen instead of through the urethra. It also uses a retention method but is placed by a different procedure.
• Foley vs. IV catheter — despite the shared word, an IV catheter goes into a vein to deliver fluids or medication, while a Foley drains the bladder. The two are unrelated in function and anatomy.

Safety and Quality Topics

Because of infection risk, hospitals track catheter use and complications closely. The term CAUTI refers to catheter-associated urinary tract infection and is a standard quality indicator. Programs commonly focus on whether each catheter has a clear reason for use, whether a closed drainage system is maintained, and whether catheters are removed promptly. Other concerns include latex allergy, discomfort, tissue injury from tension on the tube, and blockages. These topics are handled in clinical policies rather than in a general explainer like this one.

Practical Relevance for Research Administration and Procurement

For procurement and clinic managers, Foley catheters are a recurring, high-volume consumable. Several practical points come up repeatedly. First, the product range is wide, so most institutions standardize on a short list of sizes, materials, and kits to keep inventory manageable and to simplify staff training. Second, latex-free options are commonly stocked to address allergy risk, and many facilities have moved their default to latex-free for that reason. Third, shelf life and storage conditions matter, since catheters are sterile products with expiration dates and should be rotated accordingly.

Fourth, the catheter is only part of the cost. Drainage bags, securement devices, insertion trays, and specimen-collection supplies all add to the per-patient spend. Related stocking questions for drains and tubes are discussed in the drainage catheters institutional stocking guide. Fifth, any product claim about infection reduction or antimicrobial properties should be checked against the manufacturer’s documentation and, where relevant, regulatory status in your jurisdiction rather than taken from marketing language.

For research programs that include human participants with catheters, protocols should specify who places and manages the device, how output is recorded, and how adverse events are reported. Animal research that uses catheterization has its own requirements under the oversight committee’s approved protocol.

Frequently Asked Questions

What is a Foley catheter used for?

It drains urine from the bladder continuously into a collection bag. It is used during surgery, during critical illness when urine output must be measured, and when a person cannot empty the bladder for other medical reasons.

Why is it called a Foley catheter?

The name comes from the surgeon who is credited with popularizing the retention-balloon design. In everyday practice, “Foley” simply means an indwelling balloon catheter for the bladder.

How does the balloon work?

Once the tip is in the bladder, the balloon is filled with sterile fluid through a separate channel. The inflated balloon is too large to pass back through the urethra, so it holds the tube in place until the fluid is withdrawn.

Is a Foley catheter the same as an intermittent catheter?

No. An intermittent or straight catheter is inserted, used to empty the bladder, and removed. A Foley remains in place and drains continuously.

Are there latex-free Foley catheters?

Yes. Silicone and other latex-free materials are widely available, and many institutions stock them for patients with latex allergy or as their standard option.

How long can a Foley catheter stay in?

This depends on the clinical situation, the product, and institutional policy. In general, catheters are meant to stay only as long as they are needed, and the manufacturer’s instructions and clinical guidance govern any specific duration.