What type of biological agent that acts to destroy an organism by overwhelming the organism's abiility to rid itself of the poison it produces is known as a?

The type of biological agent you are referring to is known as a "toxin." Toxins are harmful substances produced by living organisms, such as bacteria, plants, or animals, which can disrupt biological functions and overwhelm an organism's ability to detoxify or eliminate them. This can lead to cellular damage, illness, or death in the affected organism.