The authors present a rationale for establishing emergency psychiatric facilities during mass demonstrations. Special aspects or attributes such as trust, confidentiality, the authoritarian role of the physician, legal complications, the management of potentially violent patients, and the evaluation of thought processes are discussed. The low incidence of psychiatric casualties and the relative rarity of adverse drug reactions during the November 1969 March on Washington are documented: the majority of the most disturbed patients came to Washington for idiosyncratic reasons and did not regard themselves as antiwar protestors.Abstract Teaser