This article reviews toxic chemicals that cause irritation and damage to single and multiple organ systems (corrosion) in an acute fashion. An irritant toxic chemical causes reversible damage to skin or other organ system, whereas a corrosive agent produces irreversible damage, namely, visible necrosis into integumentary layers, following application of a substance for up to 4 hours. Corrosive reactions can cause coagulation or liquefaction necrosis. Damaged areas are typified by ulcers, bleeding, bloody scabs, and eventual discoloration caused by blanching of the skin, complete areas of alopecia, and scars. Histopathology should be considered to evaluate questionable lesions.