Oleander (Nerium oleander), rosemary (Rosmarinus officinalis) and Pyracantha (Pyracantha coccinea) were planted for soil erosion protection purposes on the sides of Adana-Gaziantep highway. Humans and livestock consume the aforementioned plants for food although the consumption of this plants were forbidden by law. The highway emissions, mostly expected to be toxic on plants and soils, were determined in this study. Plant and soil samples were collected from the highway between Misis Industry Zone and Adana-Ceyhan highway, which have dense traffic throughout the year. Seven heavy metals (Cr, Cu, Fe, Mn, Ni, Pb and Zn) concentration were measured in plant and soil samples. The element components measured for plants for Cu, Fe, Zn, Mn, Cr, Ni, and Pb were 13.9, 172.9, 68.9, 71.3, 1.52, 62.06 and 7.3 µg g-1 respectively. Thus, the consumption of these plants should be prevented due to their heavy metal content over the allowable limits. However, the high density of those plants (Pyracantha coccinea, Nerium oleander and Rosmarinus officinalis) on the sides of highway may help to trap more heavy metals with reducing transportation to nearby agriculture and settlement areas.