paraquat poisoning

Last reviewed 01/2018

Paraquat is a poisonous dipyridilium compound whose dichloride and dimethylsulphate salts are used as a contact herbicide - the most common of which are "Weedol", "Pathclear", and "Gramoxone." Most cases of poisoning are deliberate, and the sooner treatment is commenced, the better.

Although paraquat is absorbed through the skin and mucous membranes, including the conjunctiva and bronchial mucosa, serious poisoning usually requires ingestion or injection:

  • more than 6 g is always fatal
  • less than 1.5 g is rarely fatal
  • between 1.5 and 6 g, mortality is 60-70%

In relation to commercial products:

  • a mouthful of 20% Gramoxone is almost certainly fatal
  • less than 1 sachet of Weedol is unlikely to cause death