Emodepside is a semi-synthetic product (originated by Astellas and out-licensed to Bayer for animal and human use); its precursor is synthesized by a fungus living in the leaves of Camellia japonica. It is a potent antihelminthic drug used in combination with praziquantel (as Profender®) and in combination with toltrazuril (as Procox®) for the treatment of parasitic worms in cats and dogs. Emodepside, a semi-synthetic derivative of PF1022A, belongs to a new class of anthelmintic drugs, the cyclooctadepsipeptides, and shows good efficacy against macrocyclic lactone-, levamisole- or benzimidazole-resistant nematode populations. Although putative receptors for emodepside have already been discovered, its mode of action is still not fully understood. It has being suggested that GABA(A)-receptor UNC-49 is associated with the emodepside mode of action. It has also being shown that Emodepside binds to a presynaptic latrophilin receptor in nematodes. The following presynaptic signal transduction occurs via activation of Gqalpha protein and phospholipase-Cbeta, which leads to mobilization of diacylglycerol (DAG). DAG then activates UNC-13 and synaptobrevin, two proteins which play an important role in presynaptic vesicle-functioning. This finally leads to the release of a currently unidentified transmitter. The transmitter (or modulator) exerts its effects at the postsynaptic membrane and induces a flaccid paralysis of the pharynx and the somatic musculature in nematodes.