Abstract: It is disclosed a pharmaceutical and/or phytosanitary composition comprising an aqueous extract of Chelidonium majus root and an acceptable pharmaceutical or phytosanitary excipient, for the prevention or treatment of plant infections and/or for the prevention or treatment of nail 5 infections. The composition may further comprise an aqueous extract of Thuja occidentalis leaf; and from about 1 to 5% of at least one natural phenolic compound. The composition is efficient in the treatment of plant infection (mildew fungus, blight fungus, etc); the treatment of intumescence of a plant; the treatment of potatoes (powdery or common scab, Rhizoctonia, etc), and also allows a higher crop yield: without the use of a chemical fungicide. The composition also allows rapid treatment of fungus infection of nails.