Arsenic is a dangerous chemical element with a long history of medicinal, combat, and agricultural uses. It exists within many minerals, though it can also appear as a pure elemental crystal. There are many types, with the most common being gray arsenic. The element has potent neurological effects and can dramatically damage the liver, lungs, bladder, and skin. Inorganic compounds of arsenic are typically more toxic than organic, but biological systems can convert organic compounds into inorganic compounds, making them just as dangerous.

Discovery and Writings

Albertus Magnus, or Saint Albert the Great, became the first person to isolate arsenic properly in 1250. However, despite not being able to isolate it, physicians and alchemists had been using arsenic as far back as the fourth century BCE. Hippocrates, in 370 BCE, was well aware of the toxic properties of arsenic compounds. Pedanius Dioscorides was a Greek physician and pharmacologist who served as a physician in Roman Emperor Nero’s army. He described arsenic as a poison, but also believed that it could be an effective treatment for asthma.

King of Poisons and Poison of Kings

Many empires have a long history of poisonings, though Rome stands out. Arsenic possesses no color, flavor, or odor, making it nearly indistinguishable when present in food or drinks. Additionally, its compounds were widely available, which meant that even common citizens had access. This led to arsenic becoming the poison of choice in Rome. Emperor Nero, poisoned his brother, Tiberius Britannicus,with arsenic. During the first century, the frequency of individual poisonings dramatically increased in Rome, and the popularity of this method continued for centuries.

Notable Poisoners

The Borgia family were a large and powerful family in Italy during the Middle Ages. The Borgias would add arsenic to their guests’ wine. After the visitor died, the Borgias would lay claim to the now-unowned property. This allowed the family to expand their wealth and influence. A couple hundred years later, one of the most famous poisoners in history, Giulia Tofana, came into prominence. She created “Aqua Tofana,” a mixture of various ingredients such as arsenic and lead. She marketed it as a cosmetic, allowing women who wished to be widows to purchase the poison and use it on their husbands openly. This eventually led to a long line of women poisoners following in Tofana’s footsteps.

Ancient Medicine

Arsenic’s popularity as a poison only pales in comparison to its popularity as a medication. Hippocrates used arsenic to treat various ailments, including ulcers and abscesses. In traditional Chinese medicine, the use of arsenic dates back to 200 BCE. One concept is the use of a poison to combat a poison. Some Indian herbal medicines contained arsenic, and their creators described them as capable of giving eternal life.

Liquor Mineralis

A British physician, Thomas Fowler, published a study of his arsenic solution in 1786. He called the solution “Liquor Mineralis,” and claimed it could treat malaria, fevers, and headaches. It would go on to become part of the London Pharmacopeia as “Fowler’s solution.” By the late 1800s, physicians were using this solution to treat heartburn, asthma, hypertension, tuberculosis, and many other conditions. The popularity of Fowler’s solution and arsenic led to many other arsenical solutions, such as a paste that became a treatment for breast and skin cancer.

Syphilis

In the late 1400s, King Charles VIII of France invaded Naples with an army of Spanish mercenaries. After the victory, an epidemic of a new disease spread amongst the soldiers and the citizens of Naples. It had a variety of names, the most notable being the “Great Pox.” Historians would later identify the disease as syphilis. Without treatment, the disease spread rapidly over the next 30 years. A Swiss physician, Paracelsus, first attempted to treat syphilis with an elixir containing mercury and arsenic in the early 1500s. However, it wasn’t until Paul Ehrlich, a German physician, created a “magic bullet” compound using arsenic and mercury in the early 1900s that syphilis became a properly treatable disease.

Trypanosomiasis

Ehrlich also worked with a Japanese physician named Kiyoshi Shiga between 1901 and 1905. Together, they sought treatment for trypanosomiasis. This condition, sometimes called sleeping sickness, is a group of several diseases that cause fevers, bloody urine, and aching muscles. Over time, the condition progresses, leading to confusion, slurred speech, difficulty walking, and, if not treated, death. Ehrlich’s early experiments were unsuccessful, but he eventually turned to atoxyl, a form of arsenic acid. This proved effective, but the neurotoxicity of the acid made it nonoptimal. A Swiss microbiologist, Ernest Friedheim, synthesized a derivative of atoxyl that became an effective treatment for trypanosomiasis during the 1940s.

Arsenic as a Chemical Weapon

World War I marked a turning point in warfare, particularly in the use of chemical weapons. Phosgene, chlorine, and mustard gas were common weapons of war. In 1918, the United States developed two arsenic-based gas agents to combat the Central Powers: Adamsite and Lewisite. Adamsite caused vomiting, eye irritation, and respiratory issues, and though its effects were temporary, it was still potentially fatal. Lewisite caused large, painful blisters on the skin, and if inhaled, serious respiratory infection. The United States also created treatments for these chemical agents, one of which played a role in Friedheim’s synthesis of treatment for trypanosomiasis.

Agriculture

Arsenic is not only toxic to humans, but to fungi, insects, and other pests as well. Lead hydrogen arsenate, an arsenic compound, was a popular insecticide for fruit trees. However, the compound resulted in brain damage in some of the people who sprayed the trees. Eventually, less powerful forms of arsenic would come into use as insecticides. Arsenic is also a common food additive for poultry and pigs because certain compounds prevent disease and promote weight gain.

Modern Arsenic

Despite its centuries of use as a medication, the modern view of arsenic is largely negative. This results from the extreme damage arsenic poisoning can cause, as well as how easy it is to gain access to the chemical. As a result, many countries have set limits on the levels of arsenic in products to which general citizens have regular access. Additionally, many organizations and fields of industry now use less toxic arsenic compounds or arsenic substitutes. For example, arsenic is no longer present in the cure for syphilis; penicillin is now the dominant treatment option.