Cannabis sativa L. is one of the most controversial plants worldwide, having been cultivated for over 5,000 years as both an industrial crop and a medicinal plant. It contains more than 500 bioactive metabolites, with phytocannabinoids attracting the most scientific interest due to their unique interactions with the human endocannabinoid system, which regulates key physiological processes. Among them, cannabidiol (CBD) and delta-9-tetrahydrocannabinol (Δ⁹-THC) are the most extensively studied. While CBD is non-psychotropic and widely used in various formulations, Δ⁹-THC exerts strong psychotropic effects and is subject to strict regulations in most countries. To ensure consumer safety and product quality, we developed a UHPLCHRMS/MS method for the quantification of 50 phytocannabinoids and 2 polyphenols. This method was applied to screen the rapidly expanding market of cannabis-based products, including seeds, seed oils, flour, and popular CBD oils. Notably, in addition to trans-Δ⁹-THC, its isomer cis-Δ⁹-THC was quantified, revealing significant presence in some hemp samples, underscoring the need for robust analytical tools for regulatory control. Furthermore, we assessed the safety of commercially available CBD oils by analyzing their polycyclic aromatic hydrocarbon (PAH) content, detecting alarmingly high concentrations of these carcinogenic compounds across multiple samples over several years. Beyond phytocannabinoids, Cannabis also contains a diverse array of other secondary metabolites with potential health benefits. To further investigate their role in cannabis-derived products, we quantified 52 polyphenols, including cannflavins, promising agents with strong anti-inflammatory properties, and evaluated their potential contribution to the therapeutic effects of cannabis formulations.