Ephedra alata Decne is a medicinal plant widely used in traditional medicine for the management of bronchial asthma and cancer. Phytochemical analysis and biological activities, including antioxidant and anticancer effects, were investigated in the current work as new findings for the plant E. alata, a species growing wildly in the marsh and saline environments of the central area of Saudi Arabia. The Ultra Pressure Liquid Chromatography coupled with Electron spray ionization-Quadropole-Time of flight (UPLC-ESI-Q-TOF) system was used for the phytochemical analysis of the plant constituents. In addition, Polyphenolic profiling including the total phenolic (TPC) and flavonoid (TFC) contents of the plant extracts were measured. Phenolic acids were found at the highest relative percentages among all the identified compounds and were measured at 66.07 mg GAE (Gallic acid equivalent). The UPLC analysis of the E. alata extract indicated the presence of chlorogenic acid, syringic acid, caffeic acid, vanillic acid, rosmarinic acid, umbelliferone, isorhoifolin, and apigenin at the highest relative percentages. Mineral analysis indicated that the microelement content of E. alata was relatively low, except for magnesium (Mg). In vitro antioxidant assays revealed the ability of the plant to scavenge DPPH free radicals, reduced molybdenum ions, and ferrous at levels of 14.63, 19.97, and 27.78 mg Trolox equivalents, respectively. The extract induced transition metal chelation at 31.36 mg EDTA equivalents. The extract induced cytotoxic effects against MDA-231 and A549 cell lines at IC50 levels of 25.31 and 39.81 µg/mL, respectively. The plant extract inhibited the colonization and migration of cancer cells as part of its potential anticancer effects. In addition, major E. alata constituents like isorhoifolin, chlorogenic acid, apigenin, and rosmarinic acid exhibited the lowest binding energy to the CAIX enzyme at − 8.41, − 6.64, − 6.32, and − 6.26 kcal/mol, respectively, compared to the binding energy (− 7.72 kcal/mol) of the co-crystallized ligand (Y0R). The docking results further supported the selection of the CAIX enzyme as a standard predictive therapeutic target, since it exhibited significant binding interactions with the major constituents of the plant.