This study pioneered an approach that determined the effects of excess manganese (Mn) on three species; Datura stramonium, Alhagi camelthorn and Chenopodium ambrosioides. We investigated their levels of Mn, antioxidative enzymes and oxidative damage biomarkers in plants (zone 1) in and outside (zone 2) the Mn mine. The results showed that total and available Mn were at toxic levels for plants growing on zone 1. The Mn levels in each plant species were higher in leaves, stems and roots. Mn was only accumulated significantly in leaf vacuoles of A. camelthorn. Antioxidative enzyme activities of C. ambrosioides and/or D. stramonium in zone 1 were higher in leaves, stems and then in their roots. Malondialdehyde (MDA) and dityrosine levels were insignificantly higher in tissues of the studied plants in zone 1 with respect to zone 2. The roots of studied plants showed significantly higher levels of these biomarkers in comparison with their leaves in zone 1. Accordingly, antioxidative enzymatic response to Mn-stress in D. stramonium and C. ambrosioides and possibly accumulation of Mn in leaf vacuoles of A. camelthorn, protected them from oxidative damages and involved in their tolerance in Mn mine.