<p>This paper explores the common plant–based well cement additives, their mechanism of action in well cement hydration, and their effects in cement performance properties. By exploring the historical use of phyto extracts in cementitious systems and their potential benefits in enhancing zonal isolation and structural integrity in wells, this review underscores the growing interest in eco-friendly additives. The chemical constituents of phyto extracts, including cellulose, hemicellulose, lignin, and extractives, are discussed to clarify their functional roles in tailoring properties of both fresh and hardened cement pastes. The degree to which each of these additives accounts for their synergistic effects in the cementitious system formulation is not known. Herein, we provide the chronicle of common well cement additives of plant origin, a discussion of their proposed possible mechanism of action in cement, and present some findings in the available literature on how these additives affect performance properties of cement slurry and final hydrated cement. Notably, the study focuses on the role of these extracts as fluid-loss control agents, retarders, accelerators, dispersants, lost circulation control materials, and free water controllers, highlighting their implication in mitigating issues such as premature setting, poor bonding, and compromised slurry design. The findings highlight the promising potential of organic admixtures of plant origin in cement engineering, pointing towards sustainable alternatives for future well construction applications.</p> Graphical Abstract <p></p>