The popularity of Cannabis extracts in the treatment of hard-to-manage clinical conditions and the lack of access to pharmaceutical grade Cannabis products have impacted the increase of clandestine and artisanal product consumption in Brazil. Currently, hundreds of judicial authorizations for Cannabis cultivation and artisanal extract preparation have been granted in Brazil. To evaluate the artisanal preparation techniques and improve Cannabis extract quality, preparations by patients were monitored between 2017 and 2022, and a preparation method by supercritical fluid extraction was developed. Between 2017 and 2018, the most common technique used by participants was the decoction of flowers in heated oil that provided extracts with low cannabinoid levels and the predominance of acid cannabinoids as well as high microbiological contamination. Between 2019 and 2022, decarboxylation by heating and extraction by maceration in ethanol were tested to decrease the microbiological contamination and increased the neutral cannabinoid levels in the extracts. Cannabidiol levels measured in 2021 (26.0 ± 31.1 mg/g) and 2022 (42.9 ± 15.5 mg/g) in the extracts prepared at home with pharmaceutical support were similar to industrial products and higher in cannabinoids than the products supplied by non-governmental organizations. Cannabis extracts prepared by supercritical fluid extraction at 50 °C at a pressure of 15 MPa and 800 g CO2 for 15–24 min from 9–24 g decarboxylated Cannabis flower provided cannabidiol recoveries  > 80%. Soxhlet extraction, used as a comparison method, showed excellent recoveries and is a low-cost alternative technology that is feasible to implement in community pharmacies.