Whether you're writing an essay for your university about the benefits of stem cell research or are doing research for an graffiti artist, there are a ton of places out there in which you can get information from. You just have to be careful in making sure the information you are using or citing from is legitimate. It's not hard to set up a website that gives information about activated carbon for example, which may seem like it's coming from a reputable source when in reality anyone could write such content. (We do know one source you can trust however, which you can find right here if you are interested)
If you're getting your information from textbooks assigned to you from your professor, you can most certainly be safe in assuming the materials you've been given are reliable and trustworthy. Most medical information in textbooks is given by individuals either related to or in the field of medicine. Doctors, physicians, research assistants, etc. However, when getting information on your own, you need to be aware of who is giving you that information. Do some research on the book you are reading so you can find out whether or not the information is reliable and accurate. A couple of great sources for medical research are the New England Journal of Medicine and the Canadian Medical Association Journal. You can usually never go wrong with them.
Doing research online, whether it's on tax credits or diabetes, is where you need to be extremely careful. Plenty of websites out there have no idea what they are talking about. They might seem like it but if you come across something that just sounds completely outrageous, do some research on your findings to make sure for certain. The above mentioned journals also have websites so you can't go wrong using them to crosscheck facts. Or to just to get information from them. The internet can be a dangerous place to navigate through so be careful.
Hopefully we've given you some things to consider when looking up important medical information and findings, online or in textbooks and journals. There's a lot of information out there, especially online, and you need to make sure you can trust the source you are getting your information from. Doesn't matter if you're looking up information on cosmetic surgery procedures or medicinal marijuana, you need to be safe. You wouldn't pick out a dentist without doing your research first, right? So, why write a school paper without making sure the sources you are citing from are genuine.