Milk thistle for pets: Any long-term side effects to worry about?

A large breed dog is considered a senior around 7 years of age. Milk thistle is used in some dogs mainly as liver support. The most common side effect is diarrhea. Because it is a supplement and not a medication there haven't been many studies done but anecdotally it carries few risks. You can read more at http://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=1779

Dogs are typically given milk thistle in combination with Vitamin E, Zinc and s-adenosyl methionine for liver disease. The dose is usually lower when used with these other supplements. Doses ranging from 5 mg/kg to 50 mg/kg per day have been reported to likely be safe, so 400 mg twice daily would be within this dose range. I do not typically recommend giving this supplement unless there is evidence of underlying liver disease because it is not likely to be helpful. There does not seem to be evidence of kidney disease or other problems when milk thistle supplements are used long term in dogs, but there are no studies in dogs without liver disease. I would recommend checking with your veterinarian before starting this supplement since it can potentially cause problems when given in conjunction with some other medications.

( https://vcahospitals.com/know-your-pet/milk-thistle-or-silymarin ) It is very safe to use and has a wide dosing range. I suggest for most uses, using use up to 100 mg per 10 pounds of body weight of milk thistle extract daily. Split the daily amount into 2 or 3 doses over the course of the day. Example: 13kg = 28.6 pounds. I would round up to 30#. 30 pounds x 100 mg/10# = 300mg per day. I would give 100mg three times per day or somewhere close to that dosing regimen. Too high a dose can cause an upset stomach, gas, or mild diarrhea; these are easily resolved by giving less. Hope this helps. Best wishes.

In theory this would help a pet that is being exposed to a potential liver damaging drug. It definitely won't hurt. It can be expensive however. But it is a good proactive thing to do to potentially help protect the liver from damage over time. Best wishes with your pet Tootsie moving forward. Take care. : )

slightly elevated ALT does not require immediate treatment, it could be an accidental finding especially if it is not significantly high. 1 pill once a day is enough and it cannot harm him in any way.

I'm sorry to hear that Iggy is having so many issues. Milk thistle is helpful for liver disease as it has antioxidant properties. A supplement like Denamarin contains both milk thistle and SAMe which helps the liver. Thank you for using Petco Pet Education Center, formerly Petcoach and I hope Iggy is feeling better soon!

I can't find any interaction between metronidazole and milk thistle, so you can give them to Alaska. I would give her Denamarin instead, which has Silymarin (found in milk thistle) + SAMe (not found in milk thistle. It has been tested in pets that Denamarin is far superior in effectiveness because of this added component; therefore, I always reach for Denamarin over Milk Thistle. Denamarin is often used for pets that have liver malfunction, to help promote liver regeneration. I hope this helps.