1. Veterinary dissolved composition consisting of a macrocyclic lactone or a pharmaceutically equivalent salt thereof and levamisole or a pharmaceutically equivalent salt thereof, characterized in that the pH of the composition is in the range from 2.0 to 5.0 and in which the composition contains at least 15% weight./about. surfactant. 2. The composition of claim 1, wherein the effective amount of levomizole in the composition is in the range of 6% to 27% w / v. 3. A composition according to claim 1 or 2, in which levamisole is presented in the form of levamisole hydrochloride. A composition according to claim 1, wherein the levamisole is in the form of levamisole phosphate. 5. The composition of claim 1, wherein the macrocyclic lactone is in the range of 0.2 to 1.2% w / v. 6. A composition according to claim 1, which contains a chelating agent. The composition of claim 6, wherein the chelating agent is EDTA disodium. A composition according to claim 1, which contains an antioxidant. The composition of claim 1, wherein the concentration of antioxidant in the composition is higher than 0.15% .10. The composition of claim 1, wherein the concentration of antioxidant in the composition is higher than 0.15%. 11. A composition according to claim 1, which contains a preservative. The composition of claim 11, wherein the preservative is benzyl alcohol. The composition of claim 1, wherein the composition comprises a stabilizer. A composition according to claim 13, wherein the stabilizer is ordinary glycerin. The composition of claim 1, wherein the concentration of surfactant in the composition is about 20% w / v. 16. The composition of claim 1, wherein the surfactant is polysorbate 80.17. A method of treating animals from parasitic infestation, characterized by the stage of introduction of veterinarians1. Ветеринарная растворенная композиция, состоящая из макроциклического лактона или фармацевтически эквивалентной его соли и левамизола или фармацевтически эквивалентной его с
