The Brazilian flora is one of the richest in biodiversity and has many species with high pharmaceutical and nutraceutical potential. Among these species is ora-pro-nobis (Pereskia aculeata Mill.), which stands out for the high protein content found in its leaves. The exogenous application of amino acids in crop production has shown promising results, such as the increase in productivity and plant quality, besides their capacity in alleviating environmental stress in plants. Exogenous application of L-arginine (0, 0.25, 1.0 and 2.0 g L−1 of water) was performed by drenching on coconut fiber growing media of ora-pro-nobis plants. Plant growth parameters analyzed were chlorophylls and carotenoids contents, crude protein content, and determination of enzymes and oxidative stress substances. The higher concentration of L-arginine (2 g L−1 of water) increased net photosynthetic rate, leaf area, plant fresh and dry mass, carotenoids content and crude protein content in leaves. Thus, the exogenous application of L-arginine in ora-pro-nobis plants can improve both the productivity and nutritional value of its leaves.