Chatham-Kent police administered naloxone to a 32-year-old man Sunday after they were told he was overdosing on fentanyl.
Police were contacted by a 28-year-old woman about the overdose.
Emergency services were dispatched to the location and found a man with symptoms consistent with an opioid overdose, police say.
Officers provided the naloxone to the man before paramedics arrived. He was then taken to the Chatham-Kent Health Alliance for further treatment.