The present invention provides a formulation characterised by the simultaneouspresence in cyclodextrin based supramolecular complexes, of two components,one of which possesses insecticidal, acaricidal, fungicidal, snailcidal orvermicidal activity and the other possesses an activity synergistic with thefirst, enhancing its effectiveness. The biologically active substance ischosen from the following classes of chemical products: carbamates,organophosphates, thioureas, pentatomic or hexatomic heterocycles in which 1 ,2 or 3 nitrogen atoms are present. The synergistic substance can be chosenfrom components containing at least one aromatic or non aromatic carbocyclicring, such as piperonyl butoxide, sesamol, verbutin or MGK 264. For the samedose, the activity of the present formulations is greater than that of themixture of the two active components alone or separately complexed withcyclodextrin. The process for preparing said formulation and its use for theactivities herein indicated are further aspects of the present invention.
