A method of allowing a chemical agent to absorb into a plant body, comprising a step of obtaining a dispersion which disperses aggregates in an aqueous solvent, in which the aggregate has a particle size of 100 nm or less and comprises a chemical agent contained within an amphiphilic substance and a step of bringing the dispersion obtained in step (1) into contact with at least part of a plant body to thereby allow the aggregates to absorb into the plant body.