Toxicology involves the study of the effects of substances on living organisms. At a cellular level, toxins can disrupt normal cellular function through various mechanisms. They may interact with cellular membranes, leading to increased permeability and cell lysis. Toxins can also interfere with metabolic pathways by inhibiting enzymes or mimicking substrates, causing dysregulation of cellular processes. For example, heavy metals like lead can inhibit heme synthesis, leading to anemia. Neurotoxins, such as organophosphates, inhibit acetylcholinesterase, resulting in overstimulation of cholinergic receptors. This disruption can lead to cellular injury, necrosis, and inflammation. Tissue responses vary based on the toxin's nature, route of exposure, and individual susceptibility, manifesting as organ dysfunction or failure. Understanding these mechanisms is critical for effective management in toxicology.