PURPOSE: To obtain the subject composition capable of keeping the stability of bioactive component, storable over a long period without causing agglomeration and coagulation of dispersed particles and useful as an agricultural chemical by adding fine powder of halloysite-base inorganic silicate to a specific water- base liquid composition.

CONSTITUTION: The objective composition is produced by compounding (A) a water-base liquid composition containing water as the dispersion medium and composed of fine powder of a water-insoluble or scarcely soluble bioactive substance such as fungicide, insecticide, herbicide and plant growth regular, a thickener and a surfactant with (B) 0.1-10wt.% (based on the composition A) of fine powder of a halloysite-base inorganic silicate expressed by the chemical formula, e.g., halloysite or endellite which is a hydrated aluminum silicate mineral forming halloysite by losing a part of water at about 50°C. The particle diameter of the halloysite powder is about 10-1μm. The composition has physical stability to keep high fluidity and chemical stability to keep the stability of the active component. The active component can be stably maintained in the composition.