<p>The present invention provides bis-organosulfur compounds of formulae (I) and (II) and compositions comprising the compounds that are effective against animal pests, including parasites. The compounds and compositions may be used for combating parasites in or on birds and mammals and for combating pests that damage crops, plants and plant propagation material. The invention also provides for an improved method for eradicating, controlling and preventing parasite infestation in birds and mammals.</p>
