A Chemist Forgot to Wash His Hands. 145 Years Later, That Accident Is in Your Zero-Calorie Drink.

The sweetness in your zero-calorie soda has a birthday: a Baltimore evening in 1878 when a chemist forgot to wash his hands.

The three primary documents at the center of this excavation: an 1879 chemistry journal paper, the Pure Food and Drug Act of 1906, and the Saccharin Study and Labeling Act of 1977 — the congressional moratorium that kept saccharin alive after one million Americans wrote letters to stop the FDA.

The Punchline

Saccharin was discovered by accident in 1878 at Johns Hopkins University, defended by President Theodore Roosevelt in 1907 ("Anyone who says saccharin is injurious to health is an idiot"), rescued from an FDA ban by one million consumer protest letters in 1977, and formally cleared from the U.S. National Toxicology Program's carcinogen list in the year 2000. It took 122 years to go from "coal-tar byproduct of unknown safety" to "generally recognized as safe."

Primary sources:

• Fahlberg C, Remsen I. Ueber die Oxydation des Orthotoluolsulfamids. Berichte der deutschen chemischen Gesellschaft 12: 469–473 (1879); English version in American Chemical Journal 1: 426–438 (1880) — the discovery paper, with sweetness mentioned in exactly one line
• Pure Food and Drug Act, 59th Congress, Session I, Chapter 3915 (signed June 30, 1906)
• Saccharin Study and Labeling Act, Public Law 95-203 (November 1977) — 18-month moratorium on the FDA ban proposal
• NTP (National Toxicology Program) Report on Carcinogens, 9th Edition (2000) — saccharin delisted

1. The Night He Didn't Wash His Hands

In 1877, a Russian-born German chemist named Constantin Fahlberg came to Baltimore as an expert witness in a customs dispute and ended up working in the laboratory of Ira Remsen at Johns Hopkins University. Their research focus was coal-tar chemistry — specifically, the oxidation of orthotoluenesulfonamide. Coal tar was the feedstock of the era: synthetic dyes, pharmaceuticals, and industrial chemicals were all being extracted from it in rapid succession.

One evening in 1878, Fahlberg returned home from the lab without washing his hands and sat down to dinner. He picked up his bread. It tasted unusually sweet. He tasted his water. Sweet. He licked his hand. Intensely sweet.

The next morning, he went back to the lab and tasted every beaker until he found the source. The compound would eventually be named saccharin. Its chemical structure — orthobenzoic sulfimide — made it approximately 300 times sweeter than table sugar, and because the human body cannot metabolize it, it passes out in urine almost unchanged. Caloric content: zero.

2. What the 1879 Paper Actually Says

The paper Fahlberg and Remsen published in 1879 — Ueber die Oxydation des Orthotoluolsulfamids — is primarily a study of a chemical reaction, not a report on a new sweetener. The observation that matters appears in a single sentence:

"The compound proved to be intensely sweet."

That is all. The paper's subject is the oxidation mechanism, and the sweet taste is a footnote. Neither author appears to have imagined, at that moment, that this compound would spend the next 145 years being banned, saved, banned again, and saved again.

This is a recurring pattern in the primary-source record of food chemistry: the people who discover things rarely understand what they've discovered. The meaning is added later, by someone else, often for commercial reasons.

That commercial dimension arrived in 1882, when Fahlberg traveled to Germany and began working with his uncle to develop an industrial production process. By 1884 he had committed to scaling up. By 1886 he had registered "saccharin" as a trademark and secured patents in multiple countries.

He had told Remsen nothing.

Remsen found out from a third party. In a letter to the chemist William Ramsay, he wrote:

"Fahlberg is a scoundrel. It nauseates me to hear my name mentioned in the same breath with him."

The intellectual property dispute between a laboratory director who built the foundation and a junior researcher who extracted the commercial return: this argument has not gotten simpler in the century since.

3. 1907: The President Who Liked Saccharin

The Pure Food and Drug Act was signed by President Theodore Roosevelt on June 30, 1906 — the first serious federal law regulating food and drug adulteration in the United States. Its primary champion was Harvey W. Wiley, the chief chemist at the U.S. Department of Agriculture, who had been running controlled human trials on food additives since 1902, using twelve government volunteers known as the "Poison Squad."

With the law in place, Wiley moved to restrict saccharin. In 1907, he made his case directly to President Roosevelt:

"Saccharin is a coal-tar product totally devoid of food value and extremely injurious to health."

Roosevelt's reply:

"Anybody who says saccharin is injurious to health is an idiot. Dr. Rixey gives it to me every day."

The president's personal physician had prescribed saccharin as part of a weight-management regimen. Roosevelt's lived experience of the substance — as a practical tool endorsed by his own doctor — overrode Wiley's institutional argument. The following day, Roosevelt appointed a review board of scientific experts to reconsider food additive policy. The board was chaired by Ira Remsen — the same Ira Remsen who had originally discovered saccharin and had then watched Fahlberg take full credit for it. Remsen's board concluded that saccharin was harmless in small doses. The ban was dropped.

Food policy is not decided by chemistry alone. It is decided by the people in the room, the institutions they represent, and the personal histories they carry.

4. 1977: One Million Letters

The second crisis came seventy years later.

In 1977, Canadian researchers published results from a two-generation rat study. In the first generation of rats given high doses of saccharin, 3 out of 100 developed bladder cancer. In the second generation, 14 out of 100.

The dose given to the rats was 2,500 mg per kilogram of body weight per day. Translated into human terms: this is the equivalent of a person consuming more than 800 cans of saccharin-sweetened soft drinks every day for a lifetime.

This dosage problem was already being debated at the time, but the FDA was operating under the Delaney Clause — a 1958 provision stating that any substance shown to cause cancer in animals, at any dose, could not be used in food. Under that framework, the result triggered an automatic ban proposal.

The public response was, by any measure, extraordinary.

By 1977, saccharin had become the only sweetener available to people with diabetes. Cyclamate, the previous artificial sweetener, had been banned by the FDA in 1970. If saccharin was also banned, diabetic patients would have no sanctioned alternative. The number of protest letters sent to Congress reached approximately one million.

Congress acted. In November 1977, the Saccharin Study and Labeling Act (Public Law 95-203) imposed an 18-month moratorium on the FDA's ban proposal. The law was renewed repeatedly, effectively suspending the Delaney Clause for saccharin year after year. The ban was never implemented.

The product that survived the ban carried a mandatory warning label from 1977 onward:

"Use of this product may be hazardous to your health. This product contains saccharin, which has been determined to cause cancer in laboratory animals."

Saccharin was sold in the United States for over two decades with that text on the package.

5. The Year 2000: 122 Years Later

Subsequent research clarified the mechanism behind the rat tumors. The bladder cancer in rats was not caused by saccharin directly; it was caused by a reaction between saccharin and a specific urinary protein that exists in rats but not in humans. Without that protein, the carcinogenic pathway cannot operate.

In 2000, the National Toxicology Program removed saccharin from its Report on Carcinogens. In 2001, the warning label requirement was lifted.

The compound that had been discovered in 1878, defended by a president in 1907, survived a congressional revolt in 1977, and carried a cancer warning for over twenty years had arrived, finally, at "generally recognized as safe."

6. What the Documents Teach Us About Dose

The saccharin story is a useful case study for reading any news report about a food additive and cancer.

When a study reports that a substance "causes cancer in laboratory animals," the relevant follow-up questions are: what animal, what dose, what mechanism, and whether that mechanism operates in humans. A 1977 result in second-generation rats given 2,500 mg/kg/day is not the same claim as "people who drink diet soda get cancer." The Delaney Clause treated them as equivalent. The subsequent two decades showed they were not.

In 2023, the WHO's International Agency for Research on Cancer classified aspartame — the artificial sweetener that largely replaced saccharin — as "possibly carcinogenic to humans (Group 2B)." Group 2B is the same category as coffee and pickled vegetables. The JECFA advisory panel, reviewing the same data, concluded that current acceptable daily intake levels remain safe.

The paper trail that saccharin left behind — from an 1879 footnote to a million protest letters to a 2001 warning-label repeal — is a map of how a scientific claim about food safety becomes a political event, and then, eventually, a settled fact.

7. Reading the Label

On current supermarket packaging, saccharin appears as "saccharin" or "sodium saccharin." In Japan, it is approved for use in soft drinks, pickles, sauces, and jams. The JECFA acceptable daily intake is 0–5 mg per kilogram of body weight per day — for a 60 kg adult, that is 300 mg per day. Most products contain substantially less.

The question of whether zero-calorie sweeteners help or hinder weight management is a separate and ongoing research question. The question of whether saccharin itself poses a cancer risk, at normal dietary doses, was answered in the primary documents by the year 2000.

Sources

Primary documents consulted:

• Fahlberg C, Remsen I. Ueber die Oxydation des Orthotoluolsulfamids. Berichte der deutschen chemischen Gesellschaft 12: 469–473 (1879); English version in American Chemical Journal 1: 426–438 (1880)
• Pure Food and Drug Act, 59th Congress, Session I, Chapter 3915 (June 30, 1906)
• Saccharin Study and Labeling Act, Public Law 95-203 (November 1977)
• NTP Report on Carcinogens, 9th Edition (2000) — saccharin delisted
• JECFA (FAO/WHO Joint Expert Committee on Food Additives) — saccharin evaluation, ADI 0–5 mg/kg body weight/day
• Roth K. "The Saccharin Saga." Chemistry Views (German edition 2011; English 2015) — source for the Fahlberg-Remsen correspondence
• IARC Monographs Volume 132 (2023) — aspartame Group 2B classification

This series is archival work with primary documents. Any decisions about diet, health, or food safety should be made based on current sources and professional advice.

→ Full prompt transcripts for the first seven episodes are collected in Episode 7: Templates and the first print edition.