This document provides information about urethral catheters, including who can perform catheterization, the purposes of catheterization, types of catheters, and how to properly insert a catheter. Catheterization can be used to drain the bladder, obtain urine samples, or deliver therapeutic agents to the bladder. Factors like patient age, gender, and medical condition determine the appropriate catheter size and material. Proper sterile technique and use of lubricant are important to prevent trauma and infection when inserting a catheter.