Provided are veterinary anthelmintic formulations comprising at least one macrocyclic lactone, levamisole, dimethyl sulfoxide (DMSO) and at least one humectant. The formulations may further comprise an anthelmintic benzimidazole. Examples of the humectant include propylene glycol, hexylene glycol, butylene glycol or a sugar alcohol. One of the preferred embodiments is a veterinary formulation comprising at least one macrocyclic lactone at 0.5-1% by weight, levamisole at 10-20% calculated by weight of levamisole base, DMSO at 50-80% and at least one humectant added to volume. Further provided is a method of treating internal and/or external parasites in a non-human animal using the formulations and the use of the formulations in the manufacture of a medicament for the treatment of internal and/or external parasites in an animal.
