Opioid abuse is a severe public health threat. Recent evidence points to a disturbing increase in the illicit use of fentanyl, a potent synthetic opioid, with abuse often involving illicitly produced opioids mixed with heroin. Public health experts have emphasized that there is an urgent need for new, effective harm-reduction strategies and technologies. We asked whether Internet search engines could contribute toward this goal. Using state-level data from the USA, we provide evidence for a cross-sectional and longitudinal statistical relationship between opioid-related overdose deaths and the number of Google searches using the term "fentanyl." This finding points to the relevance of Internet search engines: Userswho may be non-addicted vulnerable individuals, addicts, addicts' friends and family members, or physiciansdo in fact search for fentanyl online. We argue that during such searches, an info box including a warning (i.e., awareness material to educate users about the risks) and a help message (i.e., references to professional help) can be presented to target users and possibly prevent both unintentional and suicidal overdoses. Even if this info box only helps some users, the high number of daily Google searches renders this a promising public health intervention to supplement other opioid harm-reduction strategies.