The use of extracts from the hawthorn plant as cardiovascular agents dates back to the 1st century; recently, they have also been made available online as weight loss aids. Herein, we present a case of intentional intoxication with hawthorn root extract (HRE) in an adult patient that resulted in death. A 20-year-old female patient, who was clinically diagnosed with depression, developed hypotension, bradycardia, and depressed consciousness after ingestion of this extract. An electrocardiogram recorded a sinus arrest with a slow nodal rhythm, which rapidly deteriorated, leading to cardiac arrest. This case report illustrates the potentially fatal consequences of HRE for which the constituents have not yet been characterized. All physicians, especially those in the emergency department, should be aware of the dangerous, even potentially fatal interactions of HRE with prescription medications.