My LO put everything her mouth and i can't get her to stop. Sometimes, she threw her milk out, after putting stuffs into her mouth. How to stop her from doing this?

Babies putting things in their mouths is not only normal, but also signifies a burgeoning interest in the world around them. In their first year, babies are curious and explore their surroundings through their senses -- seeing, touching, hearing, smelling, and tasting. Putting things into their mouths is a byproduct of this development. Baby proofing the house is important to ensure that baby don't put things that can cause him to choke or get sick. I find that scrunching my face and going "ewwww" or "noooo" whenever small kids put random things in their mouth does help in deterrence to a small extent. Maybe you can consider that?

Am not sure how old is your LO. For my children, I would quickly hold their hand if they tried to stuff things into their mouth. Then I would tell them that they cannot put things into their mouth if not for eating. I got to consistently explained to them but back then, they were less than 1 yr old and talking to them, took me longer time but it was needful. My friend, on the other hand, told me she would smack her LO's hand and told her LO off fiercely.