Understand that any illegal drug can be tainted with other dangerous substances, such as fentanyl and carfentanil, which can lead to overdose and even death. Be aware that people who use drugs and alcohol can be at an increased risk of sexual assault . Never leave your drink unattended and do not accept drinks, even water, from someone you don't know. Do not mix drugs or mix drugs with alcohol. Never use drugs alone and stay with your friends and people you trust. If you choose to use drugs and are checking them with a test kit, know that test kits have limitations for detecting dangerous substances . Be aware of the dangers of drugs and alcohol . Recognize signs of an opioid overdose : It is estimated that there were 4,000 apparent opioid-related deaths in Canada in 2017 , compared to 3,000 deaths in 2016. Learn the signs of an opioid overdose: difficulty staying awake, walking or talking; very small pupils; cold and clammy skin; slow and weak breathing; choking; and extreme drowsiness or inability to wake up.