To provide a water-based microbicidal agent by selecting hinokitiol that occurs in nature and has a strong microbicidal power in order to eliminate food intoxication caused by foods and solves the problems on the hinokitiol that it has a strong smell, an irritating taste and low solubility in water, in this case the high solubilization of hinokitiol in water is needed, this water-based microbicidal agent is given to domestic animals and poultry to kill the food intoxication microorganisms in the bodies.

Extracts of aloe, green tea, Kumazasa leaves (a kind of bamboo) and Houttuynia cordata and two or more kinds of plant extracts having the same level of the functions as that of the above-stated extracts are added to hinokitiol to compensate the defects of the hinokitiol. This water-based microbicidal agent is directly given to domestic animals and poultry to reduce the cell numbers of colon bacillus, Salmonella or the like. In order to diversify the practical applications, a surfactant, an emulsifier are added to the microbicidal agent to increase the concentration of hinokitiol in the aqueous solution.