When science writer Jo Marchant felt a throbbing headache descend, she reached for a jar of candy blue capsules. Metaplacebalin Relaxant Capsules, the label read. One or two capsules to be taken three times per day. Standing by the sink, she downed two, with a glass of water. “It’s hardly a scientific trial,” she writes in Cure (Text Publishing, 2016). “But within 20 minutes or so, the pain really does dissipate.”