Petriage Clinical Insights

IMPORTANT: This article, which is provided for educational purposes only, is based on published veterinary data and decades of work with pets and pet parents. The information provided here is not designed to be comprehensive but to help you avoid the pitfalls of online misinformation and most importantly, to frame the conversation you should have with your veterinarian. Your veterinarian’s perspective may differ from what is expressed here. Always consult with your veterinarian.

Your Pet’s Mucous Membranes 

Mucous membranes are the tissues that line body cavities such as the mouth. The appearance of the mucous membranes can tell you a lot about blood circulation, oxygenation, hydration, and other aspects of your pet’s health. In a healthy pet, the mucous membranes are pink and moist. When the mucous membranes become pale or discolored, this can be a sign of a serious medical condition. Read on for tips and a visual guide to evaluating your pet. 


  • The easiest mucous membranes to evaluate are inside your pet’s mouth—the gums and inner cheeks.
  • Some breeds of dogs and the occasional cat can have black pigmented gums, which makes coloration difficult or impossible to evaluate. Use other areas like the inner part of the eyelids, or even the vulva in a female.
  • Use the attached photo guide for mucous membrane color reference. Please keep in mind there are a lot of variations between individual pets, so this index is just to give you a basic idea of the most obvious abnormal colors.
  • Sticky mucous membranes can signify dehydration. Assessing how moist or sticky mucous membranes are can be tricky and subjective, but with time and multiple observations you can develop a good sense of what is normal for your pet. The place to do this is NOT the nose of your pet, but the gum tissue!
  • Capillary refill time (CRT) is another trait that can be helpful to assess when your pet is not feeling well. However, just like assessing how moist the gums are, this takes a little practice. To check the CRT press your finger firmly on the gum tissue for about three seconds. Once you take off the pressure, the area will be paler than the surrounding tissue, but the color should return to normal in about two seconds. If it takes longer than that, it could indicate slow circulation. Your veterinarian can assess the CRT together with other symptoms your pet is probably exhibiting.
  • The point of observing your pet’s mucous membranes is not for you to make a diagnosis, but to help you assess the urgency level when your pet is not feeling well. Always consult with your veterinarian, and if possible share photos of your pet’s gums.


  • Get used to the normal appearance of your pet’s mucous membranes before there is a problem, so you have a baseline.
  • Colors on screens can look different than real life. Take a few pictures of your pet’s gums when there are no concerns, and save it on your phone for future reference.
  • If you have a dog and a cat, keep in mind that cats’ mucous membranes run a little paler than your average dog.
  • Sometimes changes in the mucous membranes’ color can be very subtle, and moreover the appearance of the mucous membranes may not correlate even to a significant medical condition. Normal-seeming mucous membranes do not rule out significant disease. If your pet is not feeling well, make sure to engage a veterinary professional with your concerns.
  • Pets with poor dental health may have bright red irritated gum tissue at the base of their teeth. When evaluating the color of a pet’s mucous membranes, be sure to look at the overall appearance instead of focusing on any small area.
  • If you ever observe tiny pinpoints of red or purple spots on the mucous membranes, these are petechiae, a serious finding which must be addressed immediately. Petechiae may be clustered closely together, or spread across a wide area, and may occur on both the gums and inner cheeks. If you find petechiae, do not delay contacting your veterinarian, because they can be an indication of a severe bleeding disorder. Better safe than sorry!


The following images will help you evaluate the color of your pet's mucous membranes.

Where to Check Color in Cats

Where to Check Color in Dogs

Color Guide & Warnings

A bright pink color is normal and healthy.
Bright red
Bright red or brick red color could be an indication of a serious systemic medical issue. However, some pets might have bright red gum tissue due to inflammation of the gum. Contact your vet for more information and guidance. 
Slightly pale
Slightly pale coloration could be an early indication of a serious condition. Contact your vet ASAP for further evaluation.
Any obviously pale coloration is a medical emergency. Contact your vet immediately.
White coloration of the mucous membranes is a medical emergency. Take your pet to the vet immediately.
This photo illustrates a dire medical situation. However, even a hint of blue or gray coloration of the mucous membranes could indicate a serious medical emergency. Contact your vet ASAP.
Faint yellow tint
A light yellow shade could indicate a serious liver disease or blood condition. Contact your vet ASAP.
Solid yellow
A saturated yellow hue of the mucous membranes indicates a medical emergency. Contact your vet ASAP.
Orange or dark yellow
A saturated or dark yellow/orange hue indicates a medical emergency. Contact your vet ASAP.