Abstract: The invention provides a pour-on formulation comprising a pyrethroid insecticide at a concentration of 7.5 to 75 kg/m.sup.3, a C.sub.6-15 alkanol diester of adipic or phthalic acid at a concentration of 150 to 800 kg/m.sup.3, a spreading agent at a concentration of 25 to 300 kg/m.sup.3, other additives at a concentration of 0 to 55 kg/m.sup.3, the balance being at least 67.5 kg/m.sup.3 of a veterinarily-acceptable mineral or vegetable oil having a kinematic viscosity at 40.degree. C. not greater than 35.times.10.sup.-6 m.sup.2 /s (35 cSt); a process for the preparation of the formulation; and its application onto a localized region of the skin or coat of an animal for combating ectoparasites.

Abstract: A method for stabilizing a rodenticidally active material selected from certain (i) indane dione derivatives, (ii) hydroxycoumarin derivatives and (iii) thiocoumarin analogs of (ii), comprising bringing said active material into contact with, and maintaining the active material in contact with, an acidic stabilizer.