Merck Manual

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Professional Version

Chlorine Bleaches


Sharon M. Gwaltney-Brant

, DVM, PhD, DABVT, DABT, University of Illinois

Reviewed/Revised May 2013 | Modified Nov 2022

Exposure to undiluted chlorine bleaches may result in GI, dermal, and ocular irritation or ulceration as well as significant respiratory irritation. All species are susceptible. Because of the countercurrent anatomy and physiology of the avian lung, caged birds are at increased risk of succumbing to fumes from bleaches and other cleaning agents.


Chlorine bleaches are primarily used as household cleaners and pool sanitizers. Household bleaches tend to contain sodium hypochlorite at 3%–10%, and pH of these products may range from 9 (mildly irritating) to >11 (corrosive). Pool treatments may contain lithium, calcium, or sodium hypochlorites at concentrations up to 70%–80%, with pH that may range from acidic to alkaline. Pets may be exposed by chewing on containers of undiluted product, drinking from buckets containing product diluted in water, or swimming in recently treated pools.


The relative hazard of a particular bleach product depends on the concentration of hypochlorite, pH, and dilution of the product. In general, levels of hypochlorite < 10% tend to be mild irritants; however, if the product has a pH >11 or < 3.5, alkaline or acid corrosive injury may occur. Dilution of bleaches with water per label directions will often reduce the corrosive potential of these products and make them little more than mild GI or ocular irritants. Mixing of hypochlorite and ammonia produces highly toxic chloramine gas that can cause acute respiratory distress or delayed onset of pulmonary edema within 12–24 hr of exposure.

Clinical Findings and Lesions:

Ingestion of dilute or moderate pH household bleach products rarely causes more than mild vomiting, hypersalivation, depression, anorexia, and/or diarrhea. Concentrated (>10%) bleach products or products with pH >11 may cause significant GI corrosive injury. Ingestion or inhalation of significant amounts of chlorine bleach occasionally results in hypernatremia, hyperchloremia, and/or metabolic acidosis. Acute inhalation may result in immediate coughing, gagging, sneezing, or retching. In addition to the immediate respiratory signs, animals exposed to concentrated chlorine fumes may develop pulmonary edema 12–24 hr after exposure. Ocular exposures may result in epiphora, blepharospasm, eyelid edema, and/or corneal ulceration. Dermal exposure may result in mild dermal irritation and bleaching of the hair coat. Oral, dermal, and ocular irritation or ulceration are possible. Respiratory lesions may include tracheitis, bronchitis, alveolitis, and pulmonary edema.


For oral exposures, emesis and activated charcoal are contraindicated; instead, dilution with milk or water is recommended. Any spontaneous vomiting should be managed, and animals should be monitored for development of GI irritation/ulceration ( see Corrosives Corrosives Acid or alkaline corrosives produce significant local tissue injury that can result in full-thickness burns of skin, cornea, and the mucosa of the oral cavity, esophagus, and stomach. All species... read more ). In cases when protracted vomiting causes electrolyte or hydration abnormalities, fluid therapy may be of benefit. For respiratory exposures, the animal should be moved to an area with fresh air and monitored for dyspnea. Stabilization of severely dyspneic animals is a must; pulmonary edema should be treated as needed. Bathing with mild shampoo and thorough rinsing is recommended for significant dermal exposures. Ocular exposures should be treated with 10–20 min of ocular irrigation with physiologic saline, followed by fluorescein staining of the cornea to detect corneal injury.

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