Abstract: The invention relates to a composition for the control of helminths in animals which contains a synergistic active ingredient combination which comprises the individual compounds of the formula I ##STR1## and of the formula II ##STR2## wherein R.sub.1 is the --NH--COO--R.sub.3 group, in which R.sub.3 is an alkyl radical of 1 to 4 carbon atoms, preferably methyl, R.sub.2 is an alkyl radical of 1 to 4 carbon atoms, preferably n-propyl, phenyl or phenyl substituted by halogen or alkyl, preferably unsubstituted phenyl, and X is --O--, --S-- or --SO--, including the acid addition salts of the compounds falling under the formula II.These synergistic compositions are used for controlling helminths, especially nematodes, in animals. The active ingredient combinations can be administered to the animals both as additive to ready prepared solid and liquid feeds and in the form of compositions, together with conventional carriers in solid or liquid form, orally, by injection, or by the pour-on method.

Abstract: The isothiocyanobenzothiazole derivative of the formula ##STR1## and also salts thereof nontoxic to warm-blooded animals have, besides generally good anthelmintic properties, especially a particularly pronounced action against filariasis, schistosomiasis and gastrointestinal helminths in warm-blooded organisms and equally against liver flukes in sheep. The active substance, together with suitable carriers and additives, is administered perorally or via the abomasum, in the form of solutions, emulsions, suspensions, powders, tablets, boluses and capsules.