20 The growing demand for medicinal plants in herbal medicine highlights their 21 therapeutic value, yet heavy metal contamination, such as cobalt (Co), poses 22 potential health risks. Cobalt's dual role as an essential micronutrient and a 23 toxic pollutant necessitates a more profound understanding of its impact on 24 medicinal plants like Adhatoda vasica. We investigated how varying Co 25 concentrations affect A. vasica shoot growth, leaf anatomy, antioxidant 26 enzyme activity, and secondary metabolite profiles. Additionally, molecular 27 docking was performed to assess the interaction of the metabolites with the 28 skin cancer-related protein anti-ssDNA antigen-binding fragment (PDB code: 29 1P7K). Low Co concentrations (50 µM) enhanced shoot dry weight by 41.45%, 30 while higher levels (100-1000 µM) reduced it by up to 66.86%. Cobalt 31 exposure increased hydrogen peroxide (H2O2) and …