Bicycle Day: Demons, Milk, and “Medicine for the Soul”

A brief history on Albert Hofmann's botched experiment with LSD that sparked a cultural phenomenon.

DoubleBlind Mag

Article by
Published on
Updated April 19, 2022

Every year on April 19th, devoted psychonauts celebrate Bicycle Day—the LSD holiday, akin to 4/20 for cannabis. But the very first Bicycle Day was nothing to celebrate for Albert Hofmann, the Swiss scientist who discovered LSD’s hallucinatory effects after accidentally dosing himself with acid. At one point, Hofmann was convinced he would not survive the ordeal that would become the basis for the holiday—and yet, dozens of trips later, he’s called it a tool for human evolution.

Find out why in our brief history of Bicycle Day.

Hofmann Invented LSD to Treat Heart and Lung Issues

The history of Bicycle Day begins in 1938, when Hofmann, who was working in the pharmaceutical department of Sandoz Laboratories in Basel, first synthesized LSD from ergot, a fungus that commonly grows on grains of rye. At the time, Hofmann had no idea that LSD had psychedelic effects. In fact, he was hoping that it would be a useful analeptic, a type of stimulant for treating respiratory and circulatory problems. 

Since analeptics were often used to help people recover from anesthesia, Hofmann’s lab began testing LSD on sedated animals. The new drug made the sleeping subjects twitch a bit, but nothing more, so the lab shelved the experiment and all other tests on LSD. 

Hofmann wouldn’t touch the substance again for another five years, but when he did, it changed his life and revolutionized psychedelic science. 

Bicycle Day—4/19/43—wasn’t Actually the First Time Someone Dosed Acid

Hofmann was the very first person to drop acid, but his first trip wasn’t on April 19th. It was actually three days earlier. On April 16th, 1943, Hofmann decided to take another look at LSD, so he started synthesizing a new batch. Just as he was finishing that process, Hofmann began feeling strange and decided to set his work aside for the day. 

After going home, he kicked back on the couch and “sank into a not unpleasant intoxicated-like condition, characterized by an extremely stimulated imagination,” he recalled in his 1980 memoir LSD—My Problem Child. “I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colors.”

Hofmann was convinced that the weird experience had something to do with LSD, which he might have accidentally absorbed through his skin while handling the substance in the lab. But he had to be sure, so he did what any mad scientist would do: experiment on himself. 

🍄 👁 🌈 ✨

How to Grow Shrooms Bundle

Take Both of Our Courses and Save $90!

Hofmann later said that he took this risky step because that’s what the new drug wanted. 

“LSD spoke to me,” Hofmann told the New York Times in 2006. “He came to me and said, ‘You must find me.’ He told me, ‘Don’t give me to the pharmacologist, he won’t find anything.’”

“LSD spoke to me…He came to me and said you must find me…When you study natural science and the miracles of creation, if you don’t turn into a mystic, you are not a natural scientist.”

That anecdote might seem bizarre coming from a respected scientist, but Hofmann didn’t believe that science and spiritualism should be mutually exclusive. 

“When you study natural science and the miracles of creation, if you don’t turn into a mystic, you are not a natural scientist,” he said in the Times interview.

It’s Called Bicycle Day Because of World War II

On April 19, Hofmann went back to his lab to drop acid—on purpose, this time—but he had no idea how much to take. The recommended dose for a first-timer is between 100-200 micrograms, according to the Global Drug Survey. But there was no way for Hofmann to know that since he was LSD’s own guinea pig. So he guessed that 250 micrograms would be a suitable dose, which he swallowed at 4:20 PM (fittingly enough).

Read: Shrooms vs. Acid

It didn’t take long for Hofmann to realize how strong a dose he had taken. After noticing that the “altered perceptions were of the same type as before, only much more intense” and that he “had to struggle to speak intelligibly,” Hofmann decided that tripping out in a chemical lab was a terrible idea, so he asked his assistant to help him get home. 

They couldn’t drive to his house because of wartime restrictions that prohibited the use of cars on public roads, so they had to bike instead. And that’s where the name Bicycle Day comes from. 

A Challenging Trip

The first Bicycle Day soon became a living nightmare for Hofmann, who began tripping even harder once he got home. “My surroundings had now transformed themselves in more terrifying ways,” he notes in his memoir. “Everything in the room spun around, and the familiar objects and pieces of furniture assumed grotesque, threatening forms. They were in continuous motion, animated, as if driven by an inner restlessness.”

At this point, Hofmann became convinced that he’d poisoned himself. The best antidote, he believed, was milk—lots of milk. Since there wasn’t any in his house, he asked his assistant to fetch some from his neighbor. But that only made things worse. 

Read: Why I Quit Microdosing LSD

“The lady next door, whom I scarcely recognized, brought me milk—in the course of the evening I drank more than two liters. She was no longer Mrs. R., but rather a malevolent, insidious witch with a colored mask.”

The neighbor wasn’t the only thing that scared Hofmann, who felt like he had been possessed. 

“A demon had invaded me, had taken possession of my body, mind, and soul. I jumped up and down and screamed, trying to free myself from him, but then sank down again and lay helpless on the sofa. The substance, with which I had wanted to experiment, had vanquished me. It was the demon that scornfully triumphed over my will.” 

“The substance, with which I had wanted to experiment, had vanquished me. It was the demon that scornfully triumphed over my will.” 

Things spiraled from there as Hofmann began to worry about losing his sanity, as well as his willpower. Soon, he began to fear that he might lose his life as well. 

“I was seized by the dreadful fear of going insane. I was taken to another world, another place, another time. My body seemed to be without sensation, lifeless, strange. Was I dying? Was this the transition?”

The most challenging parts of the experience lasted until his doctor arrived to check Hofmann’s vitals, which were normal. The only thing that seemed strange to the doctor was Hofmann’s inability to speak coherently and his “extremely dilated pupils.” 

After the doctor and the assistant helped Hofmann to bed, he began to relax and finally enjoy the trip.

“Now, little by little I could begin to enjoy the unprecedented colors and plays of shapes that persisted behind my closed eyes. Kaleidoscopic, fantastic images surged in on me, alternating, variegated, opening and then closing themselves in circles and spirals, exploding in colored fountains, rearranging and hybridizing themselves in constant flux….Every sound generated a vividly changing image, with its own consistent form and color.”

The Morning After

To Hofmann’s surprise, he woke up the next day feeling better than ever. And everything around him seemed wonderful.

“A sensation of well-being and renewed life flowed through me,” he recalled in his memoir. “Breakfast tasted delicious and gave me extraordinary pleasure. When I later walked out in the garden, in which the sun shone now after a spring rain, everything glistened and sparkled in a fresh light. The world was as if newly created. All my senses vibrated in a condition of highest sensitivity, which persisted the entire day.”

Read: Why a Drug Testing Kit for MDMA or LSD Could Save Lives

The most surprising thing to Hofmann wasn’t the afterglow of the trip, but the absence of a hangover. 

“Another surprising aspect of LSD was its ability to produce such a far-reaching, powerful state of inebriation without leaving a hangover. Quite the contrary, on the day after the LSD experiment I felt myself to be…in excellent physical and mental condition.”

Hofmann Didn’t Think LSD Would Become a Recreational Drug

Hofmann’s initial experience convinced him that LSD would have great value for researchers in pharmacology, neurology and psychiatry. But he didn’t think that LSD would catch on as a recreational substance. After his nightmarish trip, he couldn’t imagine anyone dropping acid for fun.

🍄 👁 🌈 ✨

How to Grow Shrooms Bundle

Take Both of Our Courses and Save $90!

“I had no inkling that the new substance would also come to be used beyond medical science, as an inebriant in the drug scene,” Hofmann wrote in his memoir. “Since my self-experiment had revealed LSD in its terrifying, demonic aspect, the last thing I could have expected was that this substance could ever find application as anything approaching a pleasure drug.”

In other words, he never would’ve suspected that Bicycle Day would become an annual holiday celebrated by psychonauts around the world. 

The First Official Bicycle Day

In 1985, Thomas B. Roberts, professor of educational psychology at Northern Illinois University, DeKalb, specializing in coursework on consciousness, psychedelics, the transpersonal, and mind-body relation, decided to commemorate the first LSD trip by hosting a special celebration at his home on April 19th.

“I originally wanted to celebrate the 16th,” Roberts told Catalyst in 2013, “but that year, the 16th was midweek and not a good day for a party, and the 19th was on a weekend, so I decided to celebrate the first intentional LSD exposure instead of the first exposure on the 16th.”

Read: You Can Now Buy a Microdosing Kit Online

He later said that he preferred celebrating the 19th instead of the 16th because Hofmann’s famous bike ride evoked a monumental event in American history: the midnight ride of Paul Revere.

After Roberts told friends and students about the celebration years later, Bicycle Day festivities began to spread around the world. Some enthusiasts observe the day by dropping acid, while others may take another psychedelic, or simply stay sober and honor the day by appreciating the work of psychedelic painters (such as Alex Grey, Lee Conklin, Pablo Amaringo and Laurence Caruana), listening to psychedelic music (think tributes to acid like Jefferson Airplane’s “Whie Rabbit”), or watching psychedelic movies (including 2001: A Space Odyssey and Easy Rider). 

In recent years, organized events such as concerts and museum exhibitions have been mounted to celebrate Bicycle Day.

Hofmann’s Final Thoughts about LSD

While Hofmann didn’t care for the effects of LSD at first, he gave it another shot later on and realized that his challenging trip wasn’t necessarily the norm. Between his first dose in 1943 and his death in 2008 at the age of 102, Hofmann took dozens of trips on acid, which he came to regard it as a “medicine for the soul.”

In later years, he spoke out against the worldwide prohibition of LSD, which has thwarted attempts to study the medicinal and therapeutic potential of acid for decades.

“It was used very successfully for 10 years in psychoanalysis,” he told the New York Times in 2006. “It should be a controlled substance with the same status as morphine.”

“I think that in human evolution it has never been as necessary to have this substance LSD…It is just a tool to turn us into what we are supposed to be.” 

That might happen someday thanks to renewed interest in clinical uses of LSD, which is once again being studied as a potential treatment for depression, PTSD, drug addiction, anxiety and other conditions. Those treatments will not only help the human body and mind, but improve the overall state of human evolution, according to Hofmann. 

“I think that in human evolution it has never been as necessary to have this substance LSD,” he said during a 2006 symposium that was held in honor of his 100th birthday. “It is just a tool to turn us into what we are supposed to be.” 

About the Author

Read More
Editorial Process arrow

DoubleBlind is a trusted resource for news, evidence-based education, and reporting on psychedelics. We work with leading medical professionals, scientific researchers, journalists, mycologists, indigenous stewards, and cultural pioneers. Read about our editorial policy and fact-checking process here.

Legal Disclaimer arrow

DoubleBlind Magazine does not encourage or condone any illegal activities, including but not limited to the use of illegal substances. We do not provide mental health, clinical, or medical services. We are not a substitute for medical, psychological, or psychiatric diagnosis, treatment, or advice. If you are in a crisis or if you or any other person may be in danger or experiencing a mental health emergency, immediately call 911 or your local emergency resources. If you are considering suicide, please call 988 to connect with the National Suicide Prevention Lifeline.

hand holding mushrooms
How to Take Shrooms

How Much Shrooms Should a Beginner Take?

Preparing for your first mushroom trip? We've got you.
Abstract pink and blue

Why Psychedelic Trips are So Much More Than a Series of Neurological Mechanisms

The mind is greater than the sum of its neurological parts.
LSD test kit

Why a Drug Testing Kit for MDMA or LSD Could Save Lives

Everything you should know about the best MDMA test kit and LSD test kit on the market.