The dose of our Milk Thistle is based on weight, given twice daily as follows: Under 15 lb = 0.5 mL 16 - 30 lb = 1.0 mL 31 - 45 lb = 1.5 mL 46 - 60 lb = 2.0 mL 61 - 75 lb = 2.5 ml Over 75 lb= 3.0 ml. Milk Thistle is a very safe natural supplement. while it is possible to give too much, it would have to be an exceptionally high dose.