Abstract: The present invention relates to new dithiocarbamic acid esters having the formula ##STR1## wherein R.sub.1 represents a phenyloxyphenyl or phenylaminophenyl radical which is unsubstituted or substituted by lower alkyl, halogen, trifluoromethyl, nitro or cyano, R.sub.2 represents hydrogen or lower alkyl, and alk represents lower alkylidene or lower alkylene, and also to salts of compounds of the formula (I), wherein R.sub.2 represents hydrogen, with pharmaceutically acceptable bases. These new compounds possess a strong anthelminthic activity and are useful for the treatment of warm-blooded animals infected with parasitic helminths. A specific embodiment is the N-[4-(4-nitroanilino)-phenyl]-dithiocarbamic acid-(2-carboxyethyl)-ester.