William O'Shaughnessy

William O’Shaughnessy – Forgotten Legacy

Sir William O’Shaughnessy was an Irish doctor well known of his scientific work in the areas of pharmacology, chemistry, and telegraphy inventions and use in India. His medical research led to development of intravenous therapy and introduction of wide cannabis (Cannabis Sativa) use in the Western medicine. He made cannabis the number one medicine to treat conditions from migraines to epilepsy

William O’Shaughnessy was born in Limerick on October 31st, 1809. He studied for a short period of time at Trinity College in Dublin before moving to Scotland before completing his studies. He studied forensic toxicology and chemistry. He graduated (MD) in 1829 at the Medical College of University of Edinburgh. He became William Alison’s clinical assistant in the same year.

William O'Shaughnessy
William O'Shaughnessy


In 1920s O’Shaughnessy was highly affected by two professors at the University of Edinburgh, Robert Christison (medical jurisprudence) and Thomas Hope (chemistry). Because of them his early work was in the fields of toxicology and chemistry. Although there is not much strong evidence that William O’Shaughnessy attended lectures in theoretical and practical chemistry it is clear, that as an undergraduate in Edinburgh he developed interest and proficiency for chemistry and toxicology. In 1830, at the age of 21 and a year after completing his studies he published his first paper. The paper reviewed accepted methods of detecting nitric acid in forensic cases. In July 1830 je published his second paper also in the field of forensic pathology, that emphasized the importance of accuracy in toxicological analyses.

Move to London

At approximately the same time he moved to London, where the next chapter of his career began. Shortly after moving to London, he published a new paper in the field of toxicological chemistry. He analyzed in-use methods of opium detection. It was a very important technique for the prosecution in medico-legal cases.

His next activity involved the world of forensic chemistry in food analysis, especially confectionary. The paper was published in Lancet journal in May 1831. The founder and editor of the journal, Dr. Thomas Wakley, asked him to conduct a series of analytic investigations into the truth and accuracy of various alleged adulterations in food a year before, as this would lead to an efficient public health protection.  O’Shaughnessy analyzed green, red, yellow, and blue confectionary and found dangerous substances in them. He did not quantify them (measure their quantity in the products) as it was dangerous and unnecessary that they are even present in the food. He also emphasized this should not be permitted. He also sent the results to the government.

University College London

After finding out that the rules of the Medical College do not permit him practicing medicine (he did not have the license from this college), he was forced to continue his career in the field of chemical analysis. The young doctor did not have his ambition only in the field of chemical analysis, but chemical forensic analysis as well. In the archives of University College of London there are documents stating he unsuccessfully applied for the Chair of medical jurisprudence at their institution.

As he was not allowed to practice medicine, this led him to medical politics, and he became a secretary of a group promoting London Medical College. The movement was unfortunately terminated. In his next endeavor, due to his past work, he managed to get the qualified scientist position to analyze the blood of cholera patients.


It is a fact that first cholera epidemic emerged from 1817 to 1823 however, there are still disagreements on the exact period of the second pandemic. It most probably started in 1829 and spread from Asia to Russia and the rest of Europe. It spread to Britain in October 1831. Countries formed scientific boards that headed to Russia to analyze the situation. They also tried to find a therapy and cure for cholera, as they knew it will spread all around Europe. The reports show the variety and improbability of suggested treatments. A few months after establishing a medical board in Britain, cholera reached England and took its first victim in Sunderland on October 20th, 1831.

It is then that they sent O’Shaughnessy to analyze the blood. Upon his return he presented his conclusions to the board of health (07. 01. 1832). Besides detailed analysis of past knowledge and current situation he emphasized the work of researchers Hermann and Jaehnichen, who discovered that cholera victims lost almost 30% of water in their blood. Prior to this report, he also read a paper from Dr. Stevens of West Indies. He noticed that the blood with yellow fewer patients is darker than usually.  He dosed patients with salt, so that the blood returned back to the normal red color. After many analyzes, cooperation, and experiments, O’Shaughnessy together with Thomas Aitchison Latta build the foundations for intravenous replacement therapy with fluid and electrolytes for treatment of cholera.

Cholera Instructions: London1832 (Source: Alamy)


In 1833 his life led him to work for the British East India Company (he did not manage to get the professor position at the Medical College in London) and on August 8th, 1833, he moved to Calcutta. He stayed in India and later joined the 72nd Bengal Infantry. In 1835 he joined the 10th regiment of Bengal light calvary and also became the assistant to opium agent in Bihar. On August 5th, 1835, he became the first chemistry professor at the Calcutta Medical College. He also served in Materia Medica Committee until 1840 and later became the chemistry investigator for the government. In this role he developed forensic studies methods.

Meeting Cannabis

While he lived in India, he observed the wide use of Indian cannabis for variety of health conditions. He never noticed any use of this medicine in Europe. As he was intrigued by this, he started studying traditional Indian medicine, as well as Sanskrit, Persian, and Arab writings. He wanted to create a perfect overview of current knowledge on this topic. After extensive analysis he concluded that cannabis has an exceptional power to stimulate digestive organs and affect the cerebral system. The effect of cannabis on pain mitigation had the same positive results in all cases.

Picture of Cannabis in one of O'Shaughnessy's articles and description on cannabis use and effects

William O’Shaughnessy was fascinated by the effects and started his own animal trials. He used “majoon”, which is an Arabic cannabis sweet. He gave it to a dog and reported the dog ate it with great satisfaction and later became very “drunk”. He offered “churrus” (Nepalese cannabis resin) to another dog and reported the dog became “stupid” and sleepy. In all the trials the animals recovered quickly and returned to their default state after a few hours.


In September 1839 William O’Shaughnessy faced a very interesting medical case. He was contacted by the parents of a 40-day old baby girl (the child of Mr. and Mrs. J. L. from Calcutta), who had an extreme epilepsy. She suffered from convulsive paroxysms, which increased in frequency and intensity through weeks. O’Shaughnessy used all the traditional methods, however the condition of the baby worsened further on. At this point, he acquainted the parents with cannabis and his opinion, that it can relieve their baby girl. The parents happily agreed to the cannabis experiment. Cannabis tincture was dosed on the baby girl’s tongue. Now it was time to observe.

The Effects of Cannabis Use

William O’Shaughnessy reported that the baby fell asleep in a few minutes and slept for a long time. When she woke up, she was very hungry, breastfeeding with no problem and fell back asleep (this happened at 16:00). On October 1st at 09:00, the baby was still asleep, however waking her up was not a problem. Her heart rate, face, and skin were perfectly normal. She continued with this sleepy state for 4 more days without any symptoms.  Later on (November 23rd) he reported the baby is enjoying her robust health and her natural, full, and happy outlook has returned.

O’Shaughnessy wrote about this case and many others in the Dublin Journal of Medical Science and London Provincial Medical Journal. He concluded that among all narcotics, cannabis is the safest to use. He sent a large quantity of cannabis for stock to G. Squire of Oxford Street who promised him that this extract will be available to any doctor or surgeon who wishes to use this medicine.  His wish was to widespread cannabis and accurately test it without favoritism and prejudice. His 4 years of treatment experience with cannabis convinced him that we do not have any similar medicine that would have such an anticonvulsant and antineuralgic power. It is also very thrilling to see that when closely examining the early observations scientists can confirm these claims with the current knowledge and state of the art equipment and methods.

William O'Shaughnessy drugs
Various Cannabis Products

Due to O’Shaughnessy’s promotion of cannabis as a strong drug, doctors in Ireland, Britain, Europe, and North America began with a widespread use of it. They included amazing doctors including Michael Donovan, Dominic Corrigan, Edward Birch, and Richard Greene. They all proved the efficiency of cannabis in various examples on healing migraines, neuropathic pain, trigeminal neuralgia, chorea, and opium addiction.

It is interesting to know that with today’s knowledge of endocannabinoid system we can refute all the doubts in cannabis research some people might have had in the past.


In 1856 William O’Shaughnessy received a knight’s honors from Queen Victoria for his work on telegraphy in India. He became the general director of telegraph in that time. In further years he wrote about topics connected to telegraphy including “Private Codes for Encrypted Telegraphy”. In 1860 he returned to Europe on sick leave, where his condition was unclear until he died of senile asthenia on January 8th, 1889.

His work will never be forgotten.

You can subscribe to our newsletter and like our Facebook page and never miss interesting new articles and special offers. Past articles can be found on the Dragon Blog, and you can view our current products in the online store.

G. D. C.

26. 10. 2021

Dragon Cannabis