The article explains:
http://www.dogtips.co/milk-thistle-dog-liver-problems/Symptoms of liver problems with dogs including liver disease can include a loss of appetite, lethargy, jaundice, dark urine, pale gums, changes to drinking / eating habits and a sudden change in the dog’s weight.
Milk thistle is used as a treatment for liver problems in many human liver conditions and has received generally widespread positive acclaim.
Most of the trials carried out on rats also give cause for positivity. Rats have similar liver function to dogs and there has to date been no toxic effects reported.