This toolkit is intended for frontline service providers who work with people who use psychoactive substances, who may or may not be specialized in the field of addiction, and who work in isolation wards, housing services for those who are homeless or street-involved, managed alcohol programs (wet services), drop-in services, emergency shelters and all other services that are frequented by people who use psychoactive substances. The toolkit includes info sheets that provide information on severe intoxications, overdoses and severe withdrawal (of alcohol only), the main signs and symptoms that can help us to recognize these states, and the actions to implement in order to prevent or to respond to them when they occur.