How Much Milk Thistle to Give to a Dog

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Milk thistle, also known by its scientific name of Silybum marianum​,​ is an herbal supplement that is generally safe for dogs, but before giving it to your pet, ask your veterinarian if it is right for your pup's needs. How much milk thistle your dog needs will depend on his size, the condition it's treating, and what your vet recommends.


Ask your vet how much milk thistle to give your dog.
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This herbal medication has many possible uses, including the treatment of seizures, Cushing's disease, liver problems, and pancreatitis. Learn what is generally considered to be an acceptable dose of milk thistle for dogs and why your vet may advise you to give it to your pup.


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Milk thistle benefits for dogs

The active ingredient in milk thistle is silymarin, which has beneficial effects on the liver in both humans and dogs. Most milk thistle supplements are made from the crushed seeds of the milk thistle plant because they contain the highest concentration of silymarin. It typically comes in the form of a capsule, powder, tablet, tincture, or extract.


Milk thistle has anti-oxidant and anti-inflammatory properties that may help treat a large variety of conditions, including:

  • Chronic hepatitis
  • Hepatic lipidosis
  • Liver damage and liver disease
  • Cirrhosis of the liver
  • Gallbladder issues
  • Diabetes
  • Kidney disease
  • Cancer
  • Inflammatory bowel disease
  • Mushroom poisoning
  • Pancreatitis
  • Cushing's disease
  • Allergies


Giving milk thistle to dogs

Dogs without any health problems shouldn't be given milk thistle as a preventative supplement for disease. It is typically only recommended for dogs with an existing health condition.


For example, your veterinarian may recommend milk thistle as a supplement during cancer treatment or for liver toxicity. Always be sure to follow the vet's dosing directions, as long-term usage of large doses of milk thistle may be harmful to your dog's liver.

Generally, you'll want to administer a milk thistle supplement created specifically for use in animals. That's because some tinctures crafted for humans may contain alcohol, which can be toxic to dogs.


Milk thistle dosage for dogs

Look for milk thistle supplements that contain at least 70 to 80 percent silymarin, the active ingredient in the medication that has the health benefits your dog needs. Your veterinarian can recommend a brand that has this minimum concentration and is safe for use in dogs.



For dogs with advanced liver disease, around 200 mg of milk thistle per 10 pounds of body weight may be appropriate each day. When administering milk thistle to dogs with other conditions, less than half this dose, or 60 to 100 mg per day, will usually suffice. For best results, try to divide the daily dose into two to four servings mixed into some wet food for your dog.


Although milk thistle is an herbal supplement that doesn't require a prescription from a veterinarian, it's always best to advise your veterinarian of the brand and type of milk thistle you plan on giving your dog. Because herbal supplements, like milk thistle, aren't regulated by the Food and Drug Administration, they can vary widely in terms of quality, so always follow your veterinarian's recommendations.

Milk thistle side effects for dogs

The side effects of milk thistle in dogs are usually mild and may include:

  • Upset stomach
  • Diarrhea
  • Gas
  • Nausea
  • Loss of appetite
  • Skin rashes

Because milk thistle is not recommended for use in pregnant humans due to the risk of damage to the fetus, the same precautions are recommended for pregnant dogs as well. So, if your dog is pregnant, it's best not to give her milk thistle.

Additionally, if your dog is allergic to plants in the Asteraceae family, like ragweed and daisies, it's best to avoid milk thistle supplements. That's because milk thistle is in the same family and could cause an allergic reaction.



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