A description is given of a composition suitable for forming a rodenticidal bait in paste, block or pellet form, comprising- one or more palatable solvents for rodents in which an anticoagulant rodenticidal active ingredient is dissolved,- one or more vegetable components, selected from the group consisting of flours of grain, corn, rice, barley, oat, wheat, tapioca, chestnuts, coconut, potato starch, dextrin, wood flour, wood shavings, cellulose,- one or more binding agents selected from the group consisting of vegetable fats/oils having a melting temperature higher than 36-39°C and/or paraffin wax,characterised in that it further contains calcium hydroxide as stabilizing agent of the formulation and of the active ingredient.