Arts & Life Willow: Tree Bark That Begat Aspirin Montana Public Radio | By mtpr.org Published December 6, 2013 at 8:00 AM MST Facebook Flipboard LinkedIn Email Listen • 1:29 December 7th & 9th, 2013: Willow, the original source of aspirin, is still prescribed by herbalists, particularly for urinary tract infections and muscle pain.http://www.floradelaterre.com/