lachrymatory

Lachrymatory is an adjective describing anything that causes tearing or lacrimation. In toxicology, pharmacology, and public safety, the term is commonly applied to substances that irritate the eyes and provoke reflex tearing, a reaction known as lacrimation. When used in reference to chemical agents, such substances are often called lachrymators or tear gases, especially in the context of riot control.

Etymology and usage: the word derives from lacrima, the Latin word for tear, with the combining form lachrymo- or lachrymo-. The term emphasizes the tear-inducing effect rather than the primary mode of action, which may be irritation of the ocular surface and mucous membranes.

Mechanism and effects: lachrymators irritate the conjunctiva and upper respiratory tract, causing tearing, burning sensations in the eyes, coughing, and a strong urge to rub the eyes. The intensity can vary from mild discomfort to rapid, sustained tearing that impairs vision and breathing. Effects are typically transient, but higher exposures can cause more pronounced irritation and, in some cases, longer-lasting discomfort.

Examples: common lachrymators include certain riot-control agents such as CS gas (2-chlorobenzylidene malononitrile) and CN gas (chloroacetophenone), as well as oleoresin capsicum (pepper spray) containing capsaicinoids. These substances are used to disperse crowds or deter attackers under controlled conditions, though their use is regulated due to health risks.

Regulation and history: lachrymators have a long history in crowd-control and chemical warfare. Under international law, riot-control agents may be permitted for law enforcement, while their development or deployment as weapons is prohibited. Safety guidelines and legal restrictions vary by country and context.