Background and Objective: Herbal medicinal plants are widely used in Al-Baha region, Saudi Arabia either in rural or urban areas for the treatment of several diseases. Here we investigated the phytochemical and biological effects of three herbal plant extracts, Aloe vera, Jatropha and Ricinus communis. Methodology: We have investigated the total phenolics as and total flavonoid contents of the three plant extracts. The chemical composition was determined by GC/MS. The antioxidative activity was investigated using DPPH while the antiproliferative effects were screened using the MTT assay against A549 (lung cancer, HepG2 (liver cancer) and MCF-7 (breast cancer) cell lines. Results: Total phenolic contents were shown to be 133.16±0.01, 131.60±0.06 and 44.73±0.02 mg GAE/g for Ricinus communis, Aloe vera and Jatropha, respectively, while total flavonoid contents were 19.38±0.01, 32.28±0.19 and 39.34±0.32 QE/g of dry extract. The highest DPPH scavenging potential observed was of Ricinus communis extract with IC₅₀ of 30.98 µg/ml. Six main bioactive compounds were elucidated in the GC-MS analysis of Aloe vera extract including Palmatic and stearic acids with peak areas of 45.91% and 34.27%, respectively. While 10 main bioactive phytochemical compounds were elucidated in the GC/MS analysis of Jatropha and Ricinus communis. The only observed antiproliferative was Ricinus communis methanolic leaves extracts against the three tested cancer cell lines.Conclusion:  This investigation presents insight into the phytochemical, antioxidant and antiproliferative activities of the three plants' methanolic extracts, Aloe vera, Jatropha and Ricinus communis from Al-Baha region, Saudi Arabia and provides some evidence for the medicinal properties of these plants.