We summarize our current knowledge on the recreational use of cannabis with respect to the modes of consumption, short-term effects, chronic health consequences and cannabis use disorder. Next, we overview the molecular targets of a dozen major and minor bioactive cannabinoids in the body. This helps us introduce the endocannabinoid system in an unprecedented detail: its up-todate molecular biology, pharmacology, physiology and medical significance, and beyond. In conclusion, we offer an unbiased survey about cannabis to help better weigh its medical value versus the associated risks.