A caustic is any substance capable of causing full-thickness damage on contact with healthy, intact tissue. Caustic agents are generally classified by pH as acids or bases. Irritants are those substances that do not produce true breakdown of tissue but cause discomfort and inflammation, such as vomiting, burning eyes, or coughing. This review covers caustic and irritant agents, dermal caustic exposure, caustic inhalation and pulmonary irritants, caustic ingestion, and ocular caustic exposure, along with special consideration of hydrofluoric acid, including hydrofluoric acid and dermal exposure, hydrofluoric acid ingestion, hydrofluoric acid inhalation, ocular hydrofluoric acid exposure, and systematic hydrofluoric acid toxicity. Figures show classification of burns; chemical burns; an autopsy specimen of the tongue, epiglottis, and esophagus after caustic ingestion; and an autopsy specimen of the stomach after caustic ingestion. Tables list common caustic and irritant agents, household products containing caustic and irritant agents, agents for which water or saline irrigation is not recommended, indications for endoscopy after caustic ingestion, ocular chemical burn management, and common chemicals and products containing fluoride. Key words: caustic eye injury, caustic ingestion, caustic injury, chemical burn, hydrofluoric acid, pulmonary irritants This review contains 5 highly rendered figures, 6 tables, and 53 references.