Download a free audiobook and support TED-Ed's nonprofit mission: https://adbl.co/2Hejwql Check out Oliver Sacks's "The Man Who Mistook His Wife for a Hat": http://bit.ly/2Hk8ShM View full lesson: https://ed.ted.com/lessons/what-causes-headaches-dan-kwartler In ancient Greece, the best-known remedy for a long-standing headache was to drill a small hole in the skull to drain supposedly infected blood. Fortunately, doctors today don’t resort to power tools to cure headaches, but we still have a lot to learn about this ancient ailment. Dan Kwartler shares what we know (and don't know) about headaches. Lesson by Dan Kwartler, animation by Sharon Colman. Thank you so much to our patrons for your support! Without you this video would not be possible. Senjo Limbu, Martin Lau, Robson Martinho, Jason Garcia, Cailin Ramsey, Seung Hoon Shin, John Saveland, Nicolle Fieldsend-Roxborough, Venkat Venkatakrishnan, Sandy Nasser, CG Nobles, Yoga Trapeze Wanderlust, Jaron Blackburn, Alejandro Cachoua, Thomas Mungavan, Elena Crescia, Edla Paniguel, Anna-Pitschna Kunz, Tim Armstrong, and Alessandro.