I don’t expect many cat owners to know much about milk thistle as an herbal treatment for cats and dogs. I hope that this page helps a little bit. My research indicates that it appears to have some genuine benefits as an alternative treatment. It is not radical and VCA Animal Hospitals in the US support its use. If you’re considering it, I would discuss the matter with your veterinarian first. Caution must always guide cat owners in home treatments.
Human use for thousands of years
It is a very common flowering plant of the daisy family (Asteraceae). It is a thistle and the leaves have a milky sap. Herbalists have been using the seeds of milk thistle for thousands of years, it is said, to treat liver disease and protect the liver1. For humans, milk thistle is also used to counteract the harmful effects of alcohol on the liver2. It is a natural herb and widely available to purchase as an over-the-counter medicine for people. It is promoted as a natural liver tonic and an anti-oxidant to prevent liver disease. It is claimed, “to help detox and regenerate your liver”.
The active ingredient of milk thistle seed extract is a compound called “silymarin”. So, for humans, milk thistle has beneficial effects on the health of the liver. How does this translate to cats?
Back in 2010 there was little information on milk thistle for cats
I first published this page in about 2010. At that time there was very little on the Internet about milk thistle for cats. Things have changed dramatically.
I cannot find anything on milk thistle for cats in the well-regarded books that I have on cat health. For instance, there appears to be no mention of it in the best book on cat health problems: Cat Owner’s Home Veterinary Handbook by Drs Carlson and Giffin. It is not mentioned in a book on Natural Cat Care by Dr Bruce Fogle that focuses on the sort of treatments that would include milk thistle. Medicines for people are sometimes prescribed for cats in appropriate doses (except pain killers please note), but many treatments are unsuitable.
On that assessment, it is probably fair to conclude that milk thistle for cats is on the fringes of treatments for cats. However, that is probably in part because nearly all vets use conventional medicine. There are, though, holistic vets who might prescribe milk thistle for cats.
Milk thistle for cats – 2022
A quick Google search on April 8, 2022, and I’ve found a plethora of information about treating cats with milk thistle. It is a popular herb they say and often recommended for cats who have liver disorders and who are fighting a range of conditions such as kidney issues, gallbladder conditions and cancer.
It appears to me, on a cursory glance, that the benefits for humans apply fairly well for cats as well. This is because milk thistle provides “liver support” and is therefore often used when a dog or cat becomes too ill or toxic for the body to keep the liver healthy.
The Internet tells me that it takes 2 to 4 weeks of milk thistle supplements to take effect but it will vary from cat to cat. The treatment should not be applied to pregnant or nursing animals.
What the veterinarians say about it? VCA Animal Hospitals are respected. We can take their advice with confidence. They tell us that the Latin name or scientific name for milk thistle is Silybum marianum.
As mentioned, the active ingredient is a flavonoid called silymarin. There have been scientific studies on this substance which have concluded that it has strong antioxidant and anti-inflammatory actions. It also has detoxifying actions and that it can promote cellular repair and regeneration.
Reviews of clinical studies show mixed results regarding its effectiveness. It’s effectiveness is connected to dosage. As mentioned for humans, milk thistle has a long history as a treatment for liver problems in people particularly chronic hepatitis, liver cirrhosis and gallbladder disorders. It is said to be able to stimulate the flow of bile from the gallbladder which has resulted in some herbalists recommending it to treat some bowel disorders.
Further research suggests that milk thistle can promote kidney function in feline patients with kidney damage due to diabetes and it may protect the kidneys from the toxic effects of some drugs. It has also been suggested that it can slow the growth of certain cancer cells.
It seems to have a wide range of possible uses. Veterinary herbalists and holistic practitioners have recommended milk thistle for cats for many years. It is used for the treatment of liver disorders. It is gradually becoming more mainstream in veterinary medicine.
Milk thistle seems to be safe and well tolerated in cats. The side-effects are normally mild and appear to involve the gastrointestinal tract, specifically, mild digestive upsets and diarrhoea. VCA Animal Hospitals say that it should not be used in pregnant cats.
It is available as an extract or tincture. A prescription is not needed. It is available on Amazon and I’m talking about milk thistle for cats specifically. There is one product by Pet Wellbeing which gets a very respectable 4.5/5 in reviews and is priced at £34.95 p in the UK. It appears to be supplied via a dropper onto a cat’s food. The product is described as “natural support for feline liver health”. There are other manufacturers selling this product sometimes in powder form.
There is a milk thistle powder manufactured in America and sold in the UK from All Natural. It Retails at about £15 for 4 ounces.
Milk thistle for dogs
In around 2010, research on milk thistle for pets appears to have been focused on dogs. It is claimed to help resolve these conditions:
Fatty liver, Chronic hepatitis, inflammation of the bile ducts and surrounding tissue, prevention of gallstones, inflammatory bowel disease (IBD), triaditis, to promote healing after drug therapy and/or vaccinations, cancer, hepatomegaly (enlarged liver), as an addition to treating with medicine in protozoal infections (infections caused by single celled creatures known as protozoa), poisoning from insecticides, pesticides, mushrooms and some drugs3. I sense that as there is not a lot of hard science, the true benefits may be less than is stated.
Some drug treatments can adversely affect a cat’s liver when recommended doses are exceeded. Example are: antibiotics, diuretics and Tylenol4. Bearing in mind that milk thistle has a track record for being a curative for human liver problems and that it is claimed to help prevent poisoning from drugs it may be that a holistic vet will prescribe it when treating with some conventional drugs.
It can be bought online where it is said to be a “natural treatment for liver disease in cats”. It is claimed to combat toxins and repair the liver with not side effects.
Please don’t prescribe milk thistle for cats without consulting with a veterinarian first.
1. Tamayo C, Diamond S. (2007). Review of clinical trials evaluating safety and efficacy of milk thistle (Silybum marianum [L.] Gaertn.). Integrative Cancer Therapies.6:146-157.
2.Leng-Peschlowe. Alchohol-related liver diseases-use of Legalon®. Z Klin Med 1994;2:22–7.
4. Cat Owner’s Home Veterinary Handbook by Drs Carlson and Giffin