What is LSD?

Acid, blotter, cheer, dots, drop, flash, hawk, L, lightning flash, liquid acid, Lucy, micro dot, paper mushrooms, rainbows, smilies, stars, sugar, tab, trips, tripper, window and many other names, some which describe the pictures on the squares (such as strawberries).

Lysergic acid diethylamide (LSD) is a powerful hallucinogenic drug that is derived originally from ergot, a fungus found growing wild on rye and other grasses.

As a street drug it is usually sold as a liquid that has been absorbed onto paper sheets (blotters). These sheets are subdivided into small squares, called tabs, which often have designs on them.


Various LSD tabs

LSD liquid is also occasionally dropped onto sugar cubes or formed into small tablets called microdots.

Only tiny amounts (less than 70 micrograms) are needed to get an effect and the strength of LSD can vary greatly. It is usually taken orally.


LSD was first discovered in 1938 by the research chemist, Albert Hofmann, while working to produce new medicines. In 1943 he underwent the first ever LSD trip by mistake when carrying out an experiment in his laboratory.

‘Last Friday, April 16, 1943, I was forced to interrupt my work in the laboratory in the middle of the afternoon and proceed home, being affected by a remarkable restlessness, combined with a slight dizziness. At home I lay down and sank into a not unpleasant intoxicated-like condition, characterised by an extremely stimulated condition. In a dreamlike state, with eyes closed, I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colours. After some two hours this condition faded away’.

Albert Hofmann ‘LSD: My problem child’, McGraw Hill 1980.

In the 1950s and 1960s doctors in America and the UK used LSD to help some mentally ill patients recall repressed thoughts and feelings. It was also tried out unsuccessfully by the US military as a ‘truth drug’ for interrogating enemy troops.

In the early 1960s people began to experiment with LSD use for pleasure. Among fringe and hippy groups the effects of LSD were seen as akin to a religious experience and LSD was thought of as a way of getting in touch with the self, other people and the environment. The authorities moved against LSD and in 1966 its use was made illegal in the UK. Because of the bad publicity, medical use also stopped and was prohibited by the Misuse of Drugs Act when it came into force in 1973.

LSD use declined in the 1970s and early 1980s but its popularity grew again in the late 1980s and early 1990s among young people.

The law

LSD is controlled as a Class A drug under the Misuse of Drugs Act. It is not available for medical use and is illegal to possess or supply. Maximum penalties are 7 years imprisonment and a fine for possession and life imprisonment and a fine for supply or production.

In practice, maximum sentences are rarely used. For more information please see the sentencing page on the Release website.


The Home Office statistics published in 2019 showed that 0.4% of adults 16 to 59 and 1.3% of young adults aged 16 to 24 had used LSD in the last year.

According to the National Statistics report Seizures of drugs in England and Wales, financial year ending 2021 145,140 doses of LSD were seized in the year ending March 2021, a 19% decrease compared with the previous year (180,140 doses); more LSD was seized in 2020 than in any single year since the year ending March 2005, when 1.14 million doses were recorded. They suggest that the decrease in the quantities of LSD seized could be partly due to the COVID-19 ‘lockdown’ regulations imposed during 2020-21, involving the banning of large gatherings, closures of nightclubs and music venues, and cancellation of festivals.


Users of LSD are likely to experience altered sensory experiences. These include visual effects such as intensified colours, distorted shapes and sizes, and movement in stationary objects. Distortion of sounds and changes in the sense of time and place are also common.

“My very first trip was lovely. The flowers were out and looked amazing. Everything sounded beautiful and crystal clear. I really felt at peace with myself and the world around me”.

Effects generally begin about 30 minutes after taking the drug and can last up to 12 hours, depending on the dose taken.

The effects of LSD are also dependent on how the user feels when taking the drug. Users are more likely to have a ‘bad trip’, where hallucinations are frightening and unpleasant, if they are anxious, agitated or depressed. A user may also become panicky and suffer paranoia – particularly in unfamiliar, intense or chaotic environments.

“It was at a festival. I was anxious anyway, especially as I’d already had one bad experience with acid. It started to rain and I was really scared of being drowned. I got dead paranoid. I suspected everyone around me of being out to get me. Luckily my brother found me and calmed me down but it was horrible”.

Pleasurable trips are more likely when the user is calm and in an environment where they feel safe, such as with friends. Some people claim they become more aware of themselves and others and describe LSD trips as being a spiritual experience. Feelings of being separated from the body are common.

Once LSD is taken there is no going back until it wears off. Because this can be many hours, a bad trip can be very disturbing. The same person may have good and bad experiences on different occasions and even within the same trip.

LSD may have implications for people with a history of mental health problems.

While not physically addictive, it is possible people may develop a psychological dependence to LSD. There is no evidence of anyone overdosing on LSD but people have died through accidents occurring while under the influence of the drug.

Some LSD users experience ‘flashbacks’. This is when a ‘trip’ is re-experienced some time afterwards. Flashbacks tend to be short lived but can be disturbing, especially if the user does not expect them.

There have been deaths involving LSD, in 2020 there were two deaths recorded that mentioned LSD on the death certificate according to the Office of National Statistics.

Harm reduction

  • If users do become anxious they can usually be calmed down and reassured by others – a big hug often helps (called baby-sitting). Remember that bad trips will pass in time.

“I was with a group of people and we split up and went home. I thought I’d stop tripping by then. I sat down and watched a video. There was a violent scene and I was morbidly fascinated. I sat watching it and suddenly realised I was really upset. I curled up and my hands were twisted into little claws and I started sobbing. It was very frightening and the feeling lasted with me a long time”.

  • It is difficult to concentrate while tripping and very dangerous to drive or operate machinery.
  • Do not use LSD if you are taking lithium or tricyclic antidepressants as it can interact with these substances in dangerous ways.
  • If dancing, remember to take time to rest and cool down. Sip a non-alcoholic drink slowly.
  • As with all drugs, start low by taking only a small amount.

See also DrugWise’s printable factsheet on LSD (PDF)

Updated May 2022

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