OVERVIEW
KidsHealth is a website create by Nemours, a nonprofit children’s health organization. There are three sections in the site for Parents, Teens, and Kids. As is often the case, it's the part aimed at kids which is the most useful for learners of English. There are descriptions of all the main health problems and illnesses as well as some really useful resources including quizzes, movies, and a very complete medical dictionary.
COMMENT
I've been studying the topic of health recently with my EM Normandie students, and this site has proved to be an excellent source of information, as well as providing plenty of reading and listening material at an accessible level. One useful extra is the option to hear the articles read aloud — unfortunately, it's a synthetic voice not a human one, but the quality is quite good.