Well, thanks for your concern, and I probably might think differently if Sam was a small child, however, he is 10 and weighs over 30kgs. The use of milkthistle is very beneficial for liver support, as I have said, and children with cf are always dosed at double the normal child strength for antibiotics...if anything is bound to be risky, it's the intensive use of antibiotics and the damage they may cause to the liver and other organs. Also, I dont live in the USA, and the milkthistle I obtain is regulated by the standards of my country, which I think might be a lot stricter than over there. I always select and use alternative/complementary medicines with knowledge, care and research, and expect that others would use their own initiative when doing likewise...obviously, I am another mum, not a specialist in the use of milkthistle or any other supplement, and would not expect others to adhere to my advice. It's just what I have done, there are no detrimental effects, and I use traditional medicine's logic when it comes to the dose of milkthistle. Afterall, you want enough of it to be absorbed in the gut to actually reach the site it is intended for. I suggest that others do what works for them.