Arsenic and King George III
Medication laced with arsenic may have contributed to King's mental problems

August 15, 2005

King George III (born 1738, died 1820) was ruler of Britain as the British Empire mastered the oceans and defeated France's Napoleon Bonaparte. It was also during the reign of King George III, that the United States gained its independence from the British. George III is also remembered for his poor physical health and episodes of mental instability. Scientists have suggested that these symptoms were caused by porphyria -- a rare inherited blood disorder. New studies have revealed another possible contributing cause for the King's problems : arsenic poisoning!

During his reign, George III suffered from abdominal and limb pain, rapid pulse, insomnia, anxiety, irritability and confusion. Although researchers believe that George III had porphyria, they thought that another factor contributed to the severity, late onset and persistence of the symptoms. One possible cause of these symptoms is exposure to heavy metals such as lead and mercury. Therefore, the researchers searched for signs of heavy metal exposure in a sample of the King's hair.

The Wellcome Trust and Science Museum in London gave the scientists a lock of hair from George III. The hair was taken from the King when he died and had been kept without preservatives in a black-edged envelope.

Chemical analysis of the hair revealed normal levels of mercury and slightly elevated levels of lead. Arsenic levels in the hair were extremely high, reaching a value of 17 parts per million. Arsenic poisoning occurs at levels of only 1 part per million.

The researchers point out the arsenic may worsen the symptoms of porphyria. The King was given many medications while he was sick and notes from the King's doctors suggest that some of the medicines may have been contaminated with arsenic. Repeated use of these medicines may have contributed to the severe symptoms shown by the King.

Did you Know?


  • The chemical symbol for arsenic is As and its atomic number is 33.
  • King George III was married to Charlotte of Mecklinburg-Strelitz. They had 15 children (9 boys, 6 girls)
  • At the time of his death, King George III was blind.
  • Some people believe that Napoleon Bonaparte died from stomach cancer; others believe he poisoned by arsenic.
  • A film about King George III, The Madness of King George, won the 1994 Academy Award for Best Art Direction and earned actor Nigel Hawthorne a nomination for Best Actor in a Leading Role and actress Helen Mirren a nomination for Best Actress in a Supporting Role.

References and more information:

  1. Cox, T.M., Jack, N., Lofthouse, S., Watling, J, Haines, J. and Warren, M., King George III and porphyria: an elemental hypothesis and investigation, Lancet, 366:332-335, 2005.
  2. American Porphyria Foundation
  3. Porphyria - brief summary from the National Institute of Diabetes and Digestive and Kidney Diseases
  4. Brief biography of King George III

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