How to assess pain in cats using the Feline Grimace Scale
Author: Dr Joanna Woodnutt MRCVS
Cats are notoriously skilled at masking pain, making it difficult for veterinary teams — and even experienced pet owners — to recognize discomfort early. That’s why validated pain assessment tools are so valuable. One such tool, the feline grimace scale, offers a simple yet scientifically backed way to identify acute pain in cats. Despite being available since 2019, this scale is still underutilized in many practices, often due to a lack of training.
This guide will walk you through what the feline grimace scale is, how to use it, and how to incorporate it into everyday clinical workflows to improve feline patient care.
The Feline Grimace Scale
The feline grimace scale (FGS) was developed at the Université de Montréal after researchers analyzed videos and photographs of cats experiencing pain before and after receiving pain relief. They identified five key facial cues that tend to change when a cat is in pain:
- Ear position
- Eye tightening (orbital area)
- Muzzle tension
- Whisker position
- Head posture
Each feature is scored from 0 to 2, with higher scores indicating more apparent signs of discomfort. The scale has been validated across various scenarios, including kittens, dental procedures, and surgical recovery, showing strong reliability among veterinary professionals and even caregivers at home.
Notably, the scale is most accurate when used outside the first 30 minutes following sedation or anesthesia, as those conditions can temporarily alter facial expressions. The World Small Animal Veterinary Association (WSAVA) includes the FGS in its global pain management guidelines, supporting its use in clinical and home settings.
Using the feline grimace scale in practice
To evaluate a cat for acute pain, follow these steps:
- Observation
Watch the cat quietly for 30 seconds without interruption. Make sure the cat is not grooming, eating, sleeping, or vocalizing during this period, as these behaviors may skew your assessment.
- Scoring the five facial indicators
Each facial feature is scored from 0 to 2:
Ears:
- 0 = Forward and upright
- 1 = Slightly rotated or pulled apart
- 2 = Rotated down and far apart
Eyes (orbital tightening):
- 0 = Open and round
- 1 = Partially closed or squinting
- 2 = Fully closed or tightly squinted
Muzzle:
- 0 = Relaxed and rounded
- 1 = Slightly tense
- 2 = Very tense or oval-shaped
Whiskers:
- 0 = Relaxed and curved
- 1 = Straight or slightly tense
- 2 = Pointed forward or completely straight
Head position:
- 0 = Above shoulder line
- 1 = Level with shoulders
- 2 = Below shoulders or in a hunched position
- Interpretation
Add the five scores together. A total score of 4 or higher indicates that analgesia or pain relief may be warranted. Very high scores (9–10) often require more aggressive pain management strategies compared to mild scores (4–5).
The FGS is ideal for identifying acute pain in cats, but it’s not intended for chronic pain monitoring.
4 ways to implement the feline grimace scale in your veterinary clinic
- Practice regularly and train the whole team
Accuracy improves with practice. Encourage your staff to use the FGS training tools available online, which feature photographs of cats for scoring practice. Regular team training sessions can lead to more consistent and reliable pain assessments across your clinic.
- Keep visual aids accessible
Print laminated copies of the FGS reference chart and place them in key locations—such as exam rooms, treatment areas, and feline wards. This ensures the entire team has easy access to consistent pain scoring tools during evaluations.
- Educate pet owners
Clients can be active participants in monitoring their cat’s post-operative or episodic acute pain—such as in cases of feline lower urinary tract disease (FLUTD). Because the FGS has shown reliability when used by pet caregivers, you can compare caregiver-reported scores with in-clinic evaluations for better continuity of care.
- Try the FGS mobile app
The developers of the FGS have created a companion app to walk users through the scoring process. While especially helpful for pet owners, the app can also be used by veterinary students and staff during initial training. It offers a user-friendly interface and consistent scoring support.
Other validated feline pain assessment tools
If the feline grimace scale doesn’t suit your clinic’s workflow, there are alternative options:
Unesp-Botucatu Feline Pain Scale
This scale is divided into long and short forms. The long version includes more hands-on assessments like blood pressure measurements, which may stress feline patients. The short version omits invasive steps and still provides reliable results, though palpating the affected area remains a key component.
Glasgow Composite Measure Pain Scale – Feline
While its canine counterpart is widely recognized, the feline version is less commonly used and not as extensively studied. Still, it’s another option for clinicians seeking a multi-point pain assessment method.
AI-based tools like Sylvester.Ai
This tech-forward tool uses artificial intelligence trained on multiple validated pain scoring systems, including the FGS. By uploading a photo of the cat, users receive an instant pain assessment with a confidence score. It’s ideal for tech-savvy caregivers and clinics looking to integrate data into practice management systems. Both free and paid plans are available.
Conclusion
Identifying pain in cats remains a challenge, but the feline grimace scale gives veterinary professionals, technicians, and caregivers a practical, validated way to assess acute pain. With minimal training and a structured approach, this tool can elevate the standard of feline care in both clinical and home environments.
If you haven’t already adopted the FGS in your practice, now is a great time to start.
For more feline CPD, why not look into our Feline Practice Postgraduate modular program or our Feline Nursing program
