If your students (or teachers eg. in PE or Science or Home Ec.) are after reliable health/medical information from an Australian source, try the Victorian government's Better Health Channel website. Fact sheets, patient info, image library, quizzes, medical dictionary, medicines guide, a whole kit and caboodle of stuff that's a safer bet than Wikipedia (where, apart from the issue of veracity, you sometimes run into techno-vocabulary that's beyond the scope of school kids).
The site will often come up high in Google searches, but why not direct the kids straight to a good site, rather than letting them loose in the wilderness that is health info on the internet? The language level is accessible and clear for kids to understand, and the fact that it's Australian is important (if you're in Australia) - recipes reflect local ingredients, medicines have their correct local names, further links to support groups etc aren't going to recommend a fabulous organisation in Idaho or Yorkshire...
I was going to include a graphic (the site logo), but Blogger didn't want to play. Again. Sigh.