Idea Exchange: When persistent purring is a problem
When you have a cat that just won't stop purring during its physical exam, try holding an alcohol-soaked cotton ball in front of its nose—the odor distracts it and usually results in cessation of purring. If that doesn't work, try placing your stethoscope at the xiphoid of the sternum, holding it there with the cat tucked under your arm, and turning on the tap with your other hand. The sight and sound of running water will usually make the cat stop purring.
Dr. Gina Hanfland