An aqueous suspension includes, in weight percent with respect to the total weight of the suspension, at least 10% of at least one metal in the form of salt and/or oxide and/or hydroxide, at least 3.5% of at least one polyphenol and from 0.05 to 10% of at least one dispersing agent. A process for the production of an aqueous suspension includes, in weight percent with respect to the total weight of the suspension, at least 10% of at least one metal in the form of salt and/or oxide and/or hydroxide, at least 3.5% of at least one polyphenol and from 0.05 to 10% of at least one dispersing agent, which includes a mixing step of the at least one metal, the at least one polyphenol, the at least one dispersing agent, and any other further components in water. The aqueous suspension can be used as fertilizer and/or phytoprotective agent of a plant by application of the aqueous suspension of the invention to the plant.