Ir·ri·tant, n.
 1. That which irritates or excites.
 2. Physiol. & Med. Any agent by which irritation is produced; as, a chemical irritant; a mechanical or electrical irritant.
 3. Toxicology A poison that produces inflammation.
 Counter irritant. See under Counter.
 Pure irritant Toxicology, a poison that produces inflammation without any corrosive action upon the tissues.

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