Six years after the “Benadryl challenge” first appeared on TikTok, doctors are once again warning parents and teens about the deadly phenomenon re-emerging on social media. The challenge provokes people to purposely take too much Benadryl and fight the drowsy side effects that come with it, which will produce a high. Benadryl contains the active ingredient diphenhydramine, which is an antihistamine. When used properly, the drug is meant to relieve symptoms of seasonal or situational allergies