Take vitamin C supplements when you feel a cold coming on? The problem is, you can't actually "strengthen" your immune system, says Dr. Jen Gunter. Diving into the elegant network of cells, tissues and organs that protect us every day, she introduces two kinds of immunity that specialize in recognizing and fighting off bad bacteria, viruses, fungi and toxins -- and shares what you can do to keep your immune system healthy. Think you know how your body works? Think again! Dr. Jen Gunter is here to shake up everything you thought you knew -- from how much water you need to drink to how often you need to poop and everything in between. This TED original series will tell you the truth about what's really going on inside you. Want to hear more from Dr. Jen Gunter? Follow Body Stuff on Apple Podcasts: https://link.chtbl.com/BodyStuffYT Visit http://TED.com/ to get our entire library of TED Talks, transcripts, translations, personalized talk recommendations and more. The TED Talks channel features the best talks and performances from the TED Conference, where the world's leading thinkers and doers give the talk of their lives in 18 minutes (or less). Look for talks on Technology, Entertainment and Design -- plus science, business, global issues, the arts and more. You're welcome to link to or embed these videos, forward them to others and share these ideas with people you know. Become a TED Member: http://ted.com/membership Follow TED on Twitter: http://twitter.com/TEDTalks Like TED on Facebook: http://facebook.com/TED Subscribe to our channel: null TED's videos may be used for non-commercial purposes under a Creative Commons License, Attribution–Non Commercial–No Derivatives (or the CC BY – NC – ND 4.0 International) and in accordance with our TED Talks Usage Policy (https://www.ted.com/about/our-organization/our-policies-terms/ted-talks-usage-policy). For more information on using TED for commercial purposes (e.g. employee learning, in a film or online course), please submit a Media Request at https://media-requests.ted.com/