It’s elementary: the addictions of Sherlock Holmes

Kevin R. Loughlin
Boston, Massachusetts, USA


Illustration of Sherlock Holmes for “The Valley of Fear.”
From The Strand Magazine. By Frank Wiley September, 1914.
Accessed via the Toronto Public Library, Adventures with
Sherlock Holmes virtual exhibit.

One might ask, why write about the addictions of a fictional character? The answer is that there is often a fine line between reality and fiction. The New York Times columnist Bret Stephens recently quoted a survey that found 20% of British teenagers thought that Winston Churchill was a fictional character, but 58% thought Sherlock Holmes was real.1

Another reason is that as a physician, Arthur Conan Doyle was well acquainted with the medical consequences of substance abuse. This is illustrated in The Seven-Per-Cent Solution, a “lost manuscript” of Dr. Watson written by Nicholas Meyer, who although not a physician is a Holmesian scholar who understands the mores of Victorian Britain.


The Victorian medical landscape

In order to understand the addictions of Sherlock Holmes, it is crucial to have a perspective on the medical profession’s attitude toward drugs and addiction in the Victorian era. First, however, it is appropriate to define what is meant by addiction today. The American Psychiatric Association defines addiction as “a complex condition, a brain disease that is manifested by compulsive substance use despite harmful consequence.” People with addiction (severe substance use disorder) have an intense focus on using certain substance(s), such as alcohol or drugs, to the point that it takes over their life. They keep using alcohol or a drug even when they know it will cause problems.2

There is evidence in The Adventures of Sherlock Holmes that Holmes had varying degrees of dependency on alcohol, tobacco, and cocaine. Holmes was a connoisseur of French wines. His favorites were burgundies, especially Montrachet and Meursault.3 In The Sign of Four he drank burgundy for lunch and in “The Adventure of the Gloria Scott” he drinks after dinner. But nowhere in the writings of Arthur Conan Doyle was it ever suggested that Holmes was compromised by drinking alcohol or that his behavior would be considered that of an alcoholic.3

In Victorian England, tobacco smoking by a variety of means was quite common. The British became fond of cigarettes after the Crimean War, and by the end of the nineteenth century, Britain was a smoking nation.3 However, the harmful health effects of smoking would not be recognized until decades later.

Holmes was a compulsive smoker and in that sense was addicted. He smoked cigars, cigarettes, and preferably pipes.3 He kept his cigars in the coal-scuttle and his tobacco in the toe end of a Persian slipper.4 Holmes had three pipes made from clay, briar-wood, and cherry-wood. The pipes, along with his deer-stalker hat, comprised his signature silhouette. Smoking, although a distasteful habit, would not be considered an addiction by many readers.

It was cocaine that would prove to be Holmes’ most serious nemesis. The origins of cocaine began centuries ago. The Incas of Columbia, Peru, and Bolivia chewed the coca leaf for thousands of years. They used cocaine for mystical, religious, social, and medicinal purposes.5

When the Spanish arrived, they initially banned coca as “an evil agent of the devil.” Nonetheless, the conquistadors soon realized that without what the natives called their “gift of the gods,” they could not work the fields or mine gold as efficiently.5 Coca leaves were distributed to the laborers three or four times a day.5

Coca leaves made their way to Europe and were a legal drug in England. It was widely used by physicians in Britain to treat a variety of maladies. Likewise laudanum, a tincture of opium containing 10% powdered opium by weight, the equivalent of 1% morphine, was used to relieve pain, produce sleep, and allay anxiety.6 Victorian women were prescribed the drug for relief of menstrual cramps.6

To appreciate the milieu in which Arthur Conan Doyle wrote the Sherlock Holmes mysteries, it is important to recognize that on both sides of the Atlantic narcotics and cocaine were used with and without medical supervision and without any stigma. It will seem incredulous to some that in London in 1916, Harrods was selling a kit described as a “Welcome Present for Friends at the Front” containing cocaine, morphine, syringes, and needles to be sent to the British soldiers at the front during World War I.5 Cocaine would continue to be unregulated in Britain until the passage of the Dangerous Drug Act of 1920.5


Arthur Conan Doyle, Sherlock Holmes, and cocaine

Part of Arthur Conan Doyle’s practice was ophthalmology, so it is likely that he was familiar with the medical uses of cocaine. There is no convincing evidence that he was ever a user of cocaine himself.7 However, he incorporated Sherlock Holmes’ dependence on cocaine into several of his short stories and novels.

Conan Doyle first introduces the suggestion of Holmes’ drug use in 1887. In A Study in Scarlet Watson observes, “On these occasions I have noticed such a dreamy, vacant expression in his eyes, that I might have suspected him of being addicted to the use of some narcotic.”8 Conan Doyle mentions Holmes’ habit again in The Sign of Four (1890) when he describes the detective injecting himself with a seven-percent solution of cocaine (7g of cocaine dissolved in 93g of water, forming 100g of solution).9 As Dr. Watson observes the injection, Holmes comments, “It is cocaine, a seven-percent solution. Would you care to try it?”8 In subsequent Holmes stories, Watson continues the observation of his friend’s cocaine habit. In “The Adventure of the Yellow Face” (1893) he mentions that the occasional use of cocaine is Holmes’ only vice.3

However, in none of his writings does Conan Doyle offer an explanation as to when or why Holmes began to use cocaine. The author only observed that the detective did not use it when working on a case and only to dispel boredom when he had nothing to do.3

Conan Doyle at least suggests the possibility that Holmes also had an opioid habit. In “The Man with the Twisted Lip” (1891), Watson accidentally stumbles on Sherlock Holmes disguised as an old man sitting in an East London opium den. However, Holmes assures Watson that he does not indulge in opium-smoking, but only purchased opium as part of an undercover investigation.3

However, in subsequent stories Watson begins to see his friend’s habit as more than a casual indulgence.3 In “The Adventure of the Missing Three-Quarter” (1904), Watson refers to a “drug mania” that had threatened Holmes’ career and claims to have cured him: “For years I have gradually weaned him from that drug mania which had threatened once to check his remarkable career.”8 Moreover, he adds the caveat, “Now I knew that under ordinary conditions he no longer craved for this artificial stimulus, but I was well aware that the fiend was not dead, but sleeping.”8 Nevertheless, the author leaves the ultimate disposition of the sleuth’s habit unresolved.

Not until the publication of The Seven-Per-Cent Solution: Being a Reprint from the Reminiscences of John H. Watson M.D. would a basis for Holmes’ cocaine dependence be proposed. This “lost manuscript” of the late Dr. John H. Watson was a 1974 novel by an American writer, Nicholas Meyer. The story unfolds as Holmes informs Watson of his belief that Professor James Moriarty is the “Napoleon of Crime.”10 The novel outlines this distorted reality as evidence of Holmes’ cocaine addiction. Moriarty was the childhood mathematics teacher of Sherlock and his brother, Mycroft. When Watson meets Moriarty, the professor explains the trauma he observed during Holmes’ childhood, namely that his father murdered his mother for adultery and committed suicide afterwards. It was Moriarty who had to inform the brothers of these dire events. Holmes apparently started using cocaine to suppress and escape from this memory. Through a series of deceptions, Watson leads Holmes to Vienna on the “trail” of Moriarty. The motive was to introduce Holmes to Sigmund Freud, a recovered cocaine addict himself, as part of the ruse to find Moriarty. The real intent was to enable Freud to utilize hypnosis to rid Holmes of his addiction. The novel concludes with Watson returning to London and Holmes remaining in Europe, apparently cured.


Modern lessons from historical fiction

What are the lessons to be learned from this fictional genius? In the times of Holmes, ignorance could be used as an excuse for drug abuse. However, today we are living about a century after the passage of the first legislation to make addictive drugs illegal. Ignorance can no longer be used as an excuse.

In the U.S. in 2017, there were 23,139 deaths from cocaine and 47,600 deaths from opioids. Drug-related deaths are a major public health issue, but little has been done by the medical profession or elected officials to address this problem.12

Education is the most appropriate place to start. We need to educate our patients, our colleagues, and ourselves about addictive behavior. Education must be extensive and begin early: data from the National Institute on Drug Abuse revealed that 0.5% of 8th graders, 0.8% of 10th graders, and 1.1% of 12th graders had reported using cocaine in the previous month.11

A generation ago, most medical students had little if any training about diagnosing, treating, or preventing drug addiction. These topics are now occupying an increasing presence in medical school curricula. Let all physicians heed the wisdom of Dr. Watson, “the fiend was not dead, but sleeping.”



  1. Stephens B. An antidote to idiocy in a new book about Churchill. New York Times 12/15/18
  2. [email protected] accessed 8/26/19
  3. Diniejko A. Sherlock Holmes Addictions. The Victorian Web-literature, history and culture in the age of Victoria. Accessed 5/24/18
  4. Habits and Personality-Sherlock Holmes. Sherlock Holmes 101. Accessed 8/26/19
  5. Drug that spans the ages: The history of cocaine. March 2,2006. Accessed 6/18/19
  6. Wikipedia
  7. Dis Sir Arthur Conan Doyle have any addiction? any addiction. Accessed 10/30/18
  8. A Seven-Percent-Solution-Sherlock Holmes and Cocaine. Accessed 6/18/19
  9. Percent solution/definition of percent solution by Medical dictionary. https://mediacaldictionary. The free Accessed 6/18/19
  10. The Seven-Percent-Solution. Wikipedia. Accessed 6/18/19
  11. Johnston L, O’Malley P, Miech et al. Monitoring the Future. National Survey Results on Drug Use: 1975-2015: Overview: Key Findings on Adolescent Drug Use. Ann Arbor, MI. Institute for Social Research. The University of Michigan 2015
  12. National Institute on Drug Abuse. accessed 8/27/19



KEVIN R. LOUGHLIN, MD, MBA, is a retired urologist who lives in Boston. He is a Professor, Emeritus at Harvard Medical School. He is a Trustee, Emeritus of the American Board of Urology and a former member of the board of directors of the American Urological Association. He is currently a member of the Massachusetts Historical Society and the Kennedy Library. He serves on the board of directors of the Princeton Alumni Association of New England.


Summer 2019  |  Hektorama  |  Literary Essays