Cannabis sativa is a well-known plant that has attracted a lot of attention because of its remarkable therapeutic potential. However, a variety of this species is growing invasive in some cultures in Romania. This variety has a different composition compared to the cultivated variety and a notably low Δ9-tetrahydrocannabinol (THC) content, making the occurrence of psychoactive effects highly improbable. This research aimed to evaluate from a pharmacognostical point of view the herbal drug collected from Romania. A preliminary microscopic analysis was performed to confirm the identity of the herbal drug. A qualitative analysis by thin-layer chromatography was performed to identify cannabinoids and flavonoids. Quantitative determinations included the evaluation of total polyphenolic content, total flavonoid content, and hydroxycinnamic acid content, as well as ion chromatographic analysis for anion quantification. Antioxidant and alpha-amylase activities were performed as well. The results indicated that the herbal drug contains only moderate concentrations of polyphenolic compounds, but has a good antioxidant activity, likely attributable to the presence of non-polyphenolic compounds. Moreover, the extract had a moderate alpha-amylase inhibitory activity, suggesting a low potential in nutritional and therapeutic contexts.