Background: Guidelines from the World Health Organization for managing foodborne disease outbreaks caution about the following possible causes: pathogenic bacteria, viruses, protozoa, trematodes, cestodes, nematodes, natural toxins, and chemicals, but not medicines (1). Objective: To report a foodborne disease outbreak caused by clonidine. Methods and Findings: On 23 April 2010 at 11:50 a.m., travelers who had just finished lunch at a restaurant in the Huairou District, Beijing, China, began to feel faint. By 2:30 p.m., 80 people comprising 43 men and 37 women with a median age of 32.4 years (range, 20 to 75 years) developed dizziness (100%), weakness (87.5%), lethargy (76.3%), dry mouth (67.5%), nausea (31.3%), blurred vision (26.3%), vomiting (20.0%), perioral numbness (15.0%), dysarthria (8.8%), and tinnitus (6.3%). The median incubation period was 30 minutes (range, 15 to 90 minutes). © 2013 American College of Physicians.