National Poisons Information Service

A service commissioned by Public Health England




Members of the public

seeking specific

information on poisons

should contact:


In England and Wales:

NHS 111 - dial 111


In Scotland:

NHS 24 - dial 111


In N Ireland:

Contact your local GP or

pharmacist during

normal hours; click here

(www.gpoutofhours for GP

services Out-of-Hours.


In Republic of Ireland:

01 809 2166



professionals seeking

poisons information

should consult:


Patients may become exposed to cyanide-containing compounds from a variety of sources either by ingestion, through the skin or by inhalation. Ingestion of cyanide salts, either deliberately or accidentally, can have potentially serious or fatal effects and cyanide may also be found as a product of combustion (together with other toxins), for example from house fires or cigarettes. Some foods contain cyanogens, and eating these in excess can result in raised concentrations of cyanide in the body.


During 2015/16, 95 telephone enquiries were made to the NPIS where the caller was concerned about exposure to cyanide, a cyanogen, or where the presence of cyanide was recorded. Of these, 38 involved a cyanogen-containing plant, 26 a call where cyanide was discussed as a possible toxin from products of combustion, 19 where hydrogen cyanide or a cyanide salt was the cause of concern and three following exposure to acrylonitrile. The source was unknown in nine cases.


Where the gender was known, females were involved more commonly following plant exposures (22F v 13M), while men were much more commonly exposed to cyanide and its salts (3F v 16M); putative cyanide exposure to products of combustion occurred almost equally between genders (11F v 12M). 


Of the 95 exposures, 75 occurred in a domestic situation and 10 at work. The majority of putative domestic exposures were due to plants (38) and products of combustion (24) with eight involving cyanide or a cyanide salt. Of the 10 workplace exposures, none involved either plants or products of combustion: seven were due to cyanide and its salts, two to acrylonitrile and one to an unknown compound.


The severity of features present at the time of the enquiry is recorded using a poisons severity score. Of the 38 enquiries involving plants, 25 were asymptomatic, 12 had minor features and one had moderate features. No patient had severe effects. In contrast, of the 26 cyanide enquiries concerning products of combustion, three were asymptomatic, nine had minor features, four moderate and nine severe features. In enquiries concerning cyanide salts, six were asymptomatic, seven had minor features, five moderate effects and one had severe effects. Of the three acrylonitrile enquires, one was asymptomatic and two had minor features only. The severity was not recorded in nine cases.


In the absence of a clear history of cyanide poisoning, diagnosis may be difficult as it is not possible to obtain analytical conformation rapidly enough to influence initial management. Whilst it is important to consider the possibility of cyanide exposure from products of combustion, it is fortunate that cyanide concentrations fall as soon as the patient is removed from the source of exposure.


Information from the NPIS Annual Report 2016/17.


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