This paper presents generic models for the effect of a chemical toxin on cells forming the tissue of an organ. The models are illustrative, not specific to organ or toxin. Interactive response of within-tissue toxin and cells is modeled: cell capability to modify (metabolize or bind) toxin is represented, as is the alteration of that capability by toxin presence. Both processes are represented in the context of simple versions of the cell cyde. Toxin-cell interaction is explicitly represented in terms of inter-cell chemical signaling that encourages replacement or repair of cells. The impact of cell death by apoptosis and necrosis is represented in terms of within-tissue toxin concentration. The model is explicitly stochastic, representing inter-cell and toxin input and within-organ concentration in terms of diffusion approximations. Explicit mathematical discussion is given of dose-response function behavior at low doses.