The use of plants has grown constantly worldwide, being a rich source of compounds that serve as established treatments for various diseases and conditions. This paper discusses the elemental composition and the level of environmental risk of heavy metals of selected medicinal plants. The extracts are investigated by energy dispersive X-ray fluorescence, a non-destructive, fast, multi-element, highly accurate and environmentally friendly analysis compared to other elementary detection methods. The studied plants Croton dioicus and Phoradendron villosum are native to Mexico. Both showed high levels of Cu and Ni, while their extracts present levels within the permissible range.