To inexpensively and efficiently produce a metal salt mixture compris ing salts of minute quantities of essential metals, zinc, copper, iron and manga nese, and salts of usual quantities of metals, calcium, potassium, magnesium and sodium from papaya in a preferable state for ingestion to human body.

This metal salt mixture comprising salts of minute quantities of essential metals, zinc, copper, iron and manganese, and salts of usual quantities of metals, calcium, potassium, magnesium and sodium, is readily prepared in high yield by drying leaves, petrioles, stems or rhizome parts of papaya widely cultured in regions between subtropical and tropical zones, firing and carbonizing it alone or by an electric furnace and then extracting it with water or an aqueous medium. As this metal salt mixture contains abundantly vitamins, it is appropriate for ingestion to human body, capable of widely utilizing it and useful for effectively utilizing leaves, petrioles, stems and rhizomes dumpted in the past.