Olive Leaf Extract for Cats: What You Need to Know

Olive leaf extract contains plant compounds call polyphenols, particularly oleuropein and hydroxytyrosol. These have been studied for anti-inflammatory and antioxidant activity, as well as for other biological effects, including the ability to reduce or modulate blood sugar levels in diabetes and support healthy blood pressure. 

Additionally, olive leaf extract can interact with harmful intestinal bacteria, and one study showed that it improved heart health in rodents.  

The evidence for benefits of olive leaf extract is based on human trials, rodent research, and lab studies. Unfortunately, cat-specific research is lacking, so there isn’t direct evidence that it can benefit cats.  

Olive leaf has wide-ranging and sometimes powerful biological actions. Because of this, it’s best to use olive leaf extract in cats under the supervision of a veterinarian and only for a specific purpose. Don’t give your cat an olive leaf extract formulated for people, which may provide too large a dose for a feline. 

The side effect profile of olive leaf extract in cats hasn’t been well studied. However, as with any other supplement, if your cat is taking olive leaf extract, watch for any changes in their behavior or health. If your cat is already on medications, your veterinarian may also recommend bloodwork before and shortly after starting the supplement.  

If you see any of the following symptoms, stop giving your cat the supplement:  

• Vomiting  
• Diarrhea  
• Changes in their eating or appetite  
• Behavior changes  
• Changes in sleeping patterns  
• Low or reduced energy (lethargy)  

If your vet has a specific reason to consider olive leaf extract, use only the exact product they recommend and follow their directions closely. Don’t guess at amounts, split human capsules, or mix and match brands, because nutraceutical dosing and potency may not be standardized.  

If you think your cat swallowed too much olive leaf extract, call your veterinarian, an emergency hospital, or the Pet Poison Helpline (855-764-7661) right away. Keep the package nearby so you can share the ingredient list and concentration. Since supplement strength can vary, it’s safest to treat any possible overdose as a time-sensitive urgent situation.  

Is olive leaf extract the same thing as olives or olive oil? 

No. Olive leaf extract comes from the leaves of the olive tree, while olives are fruit and olive oil is made from that fruit, so they are different ingredients.  

Is there proof that olive leaf extract helps cats? 

There is no solid proof that it helps cats. Cat-specific research is lacking, so it’s best to use it cautiously and only with veterinary guidance. 

Could olive leaf extract interact with my cat’s medicine? 

Yes. Research on interactions is lacking, which is a good reason to check with your veterinarian before giving any herbal supplement.  

Why do people still ask about it if the evidence is limited? 

Olive leaf compounds are studied in lab, human, and rodent research, and the ingredients sound promising. However, promising research is not the same as a proven feline benefit.