A method for exterminating existing infestations of termites, insects or other living organisms in structures, soils and other materials using a capsicum-containing killing solution in either a liquid or vapor form, including the steps of delivering the killing solution to the infested portions of the structure, and contacting the termites, insects or other living organisms forming the infestation. The method obviates the need for toxic or environmentally unsafe chemical compounds, and capsicum is readily available and economical. More importantly, the novel pesticide and method of use of the present invention is highly effective against termites in dry areas, wet areas, inaccessible and exposed areas, including around and under foundations, in ceiling and in wall portions of structures. Boring small holes into the structure, from either the inside or the outside and penetrating into the interior wall, ceiling and foundation spaces will allow the capsicum based killing solution to be pumped directly therein. Additionally, the killing solution can be applied underneath vapor barriers into the soil to eliminate nematodes in soil prior to other agricultural activities.