I need some help about website that provide imformation about what can or can't bring from over seas?

My parent coming to visit me in washing from thailand but frist they lands in los angeles and they going to bring some food and medication from overthere. I not sure they allowed to do that ? if they have something they not allowed what officer going to do to my parents? I am so worry that officer will ask they a question and they can't answer cause my parents don't speak , read , or write any english. are they going to have interprater speak THAI for my parents? any answer will help. thanks alot.