Friends and family of a recently deceased 15-year-old girl in Oklahoma City are warning the public of the dangers of the so-called “Benadryl Challenge” on TikTok, in which users take a dozen or more doses of diphenhydramine hydrochloride, the active ingredient in Benadryl, to cause hallucinations. “The dose that can cause a hallucination is very close to the dose that can cause something potentially life-threatening,” Scott Schaeffer, director of the Oklahoma Center for Poison and Drug Information, told KFOR, a local news channel. According to Schaeffer, large doses of the drug can cause seizures and heart issues. In response, Benadryl’s manufacturer, Johnson & Johnson, told the Daily Mail that it was working with TikTok to warn the public and remove content from the site.