Cannabis has a long and controversial tradition. A narrative review was conducted in 2024 with the aim of analyzing the discrepancies in the reclassification of cannabis for medical use and research in 2020. Indexed journals, scientific digital resources, reports from international organizations, States and expert opinions from institutions and scientists were critically examined. The results showed scientific evidence on risks and possible benefits, with a complex, biased, contradictory and inconclusive history. The damage to health and life led to its classification in an international regulatory legal framework, violated by drug trafficking and the patenting of molecules that do not meet the requirements as drugs, trivializing their abuse. After legalization, abuse, trafficking and harm increased, especially among young people. The pro-legalization environment of high-potency cannabis in a globalized world has decreased the perception of risk, even among health personnel, distorting communication. The thriving cannabis industry, with its sophisticated marketing, attracts young people. It was concluded that methodological and practical inconsistencies persist in research, weakening the international drug control regime. The benefits of reclassification are not evident; on the contrary, abuse, trafficking, physical and mental illness, indirect deaths and damage to the environment continue to increase, which could lead to the legalization of all drugs, threatening human health and survival.