The invention relates to a kind of animal agentia and the preparative of it, which has something to do with the animal drug technology. The material of the agentia is plantaginis, which can relieve the fever, induce urination, intoxicate and eliminate phlegm. The making procedures go as follows: remove the impurities of plantaginis and clean it thoroughly; cut it into several sections and crush the plantaginis; extract the smashed plantaginis; mix the filtered solutions together; dry the solution into powder and smash it into refined plantaginis powder. The extracting procedure includes two steps mainly, the first step is extracting the material in solution at ph2-5(adjusted by 10% acid solution) for 2 hours; the second step is extracting the material in solution at ph8-9(adjusted by 10% acid solution) for 8-9 hours. The agentia can treat the loimia of livestocks and poultries very effectively. The processing technology adopts the water-extracting method, besides it adopts acids before alkaline during extracting so that it can retain the effective ingredient of the drug. The effective ingredients of the refined powder have overcome the absorption problem of plantaginis, so that the agentia can increase the economic benefits and decrease the producing cost of the animal agentia.