Which toxins can cause death within minutes to a few hours?

Toxins that can produce death within minutes to a few hours include cyanide (inhaled or ingested, causing rapid cellular hypoxia and treatable with hydroxocobalamin or sodium thiosulfate), carbon monoxide (high‑level inhalation leading to severe hypoxic injury, treated with 100 % oxygen or hyperbaric oxygen), hydrogen sulfide (inhalation causing immediate respiratory paralysis, managed with supportive ventilation and sodium nitrite/ thiosulfate), botulinum toxin (type A or B from contaminated food, causing neuromuscular blockade, treatable with antitoxin and aggressive respiratory support), ricin (inhalation or ingestion of the plant protein, producing multi‑organ failure, managed with supportive care and experimental antitoxin), tetrodotoxin (puffer‑fish consumption, causing profound sodium‑channel blockade and paralysis, treated with supportive ventilation), strychnine (ingestion leading to uncontrolled muscular convulsions and respiratory failure, managed with benzodiazepines and airway protection), organophosphate insecticides (acute exposure causing cholinergic crisis, treated with atropine, pralidoxime, and benzodiazepines), aconitine (from monkshood plant ingestion, causing severe cardiac arrhythmias, managed with sodium bicarbonate and advanced cardiac life support), arsenic (massive acute ingestion causing gastrointestinal hemorrhage and cardiovascular collapse, treated with dimercaprol or succimer), and severe chlorine or ammonia gas inhalation (causing airway burns and pulmonary edema, requiring immediate decontamination, oxygen, and ventilatory support). In any suspected exposure to these rapidly lethal toxins, immediate emergency medical care, airway protection, high‑flow oxygen, and administration of the appropriate antidote when available are essential, and advanced supportive measures such as intubation, mechanical ventilation, and cardiovascular support should be instituted without delay.