Ketamine is a hallucinogenic dissociative and anaesthetic that is used in both humans and animals for medical purposes. It was synthesised in 1962, and used in anaesthesia as an alternative to phencyclidine (PCP) which caused powerful, long lasting hallucinations and psychotic symptoms. Today it is often used as an anaesthetic in children or those undergoing minor surgery. It is most frequently used now in veterinary medicine. It is on the World Health Organisation’s list of essential medicines.

In low doses, users report a similar feeling to being drunk. Higher doses cause a much more dissociative or psychedelic effect. When used as a medicine, ketamine is a clear liquid. “Street” ketamine is usually a white powder; with a grainy appearance like salt, or flaky like tiny glass shards.

Please read ME for more general information about recreational drugs.


Don't mix with alcohol


Don't take it alone


Safe setting


We have listed the most common effects of ketamine. Please note that everyone can be affected differently, and this is not an exhaustive list. Not everyone experiences these effects, and other effects are possible.

The effects are (from positive to negative):

    • Increase in energy
    • Euphoria
    • Sense of calm and serenity
    • Meaningful spiritual experiences
    • Enhanced sense of connection with the world (beings or objects)
    • Distortion or loss of sensory perceptions
    • Closed and open eyes visuals
    • Dissociation of mind from body- in large doses users may experience a “k-hole” which is an intense out-of-body or near-death like experience with very realistic visuals.
    • Changes in how you perceive time
    • Pain relief/numbness
    • Shifts in perception of reality
    • Slurred speach
    • Some short term memory loss may occurs- and this is worse for regular users! Users may find it difficult to remember what happened when they have taken ketamine. When people take a lot of ketamine, they are unable to form new memories while they are high and therefore may experience a blackout, with little-to-no memory of the experience.
    • Nasal discomfort when snorting
    • Discomfort, pain or numbness at injection site (only when injected)
    • Severe confusion, disorganised thinking
    • Paranoia (with regular use)
    • Nausea and vomiting
    • Frightening or untimely distortion
    • Loss of control of body movements and balance. Becoming uncoordinated, finding it difficult to move around
    • Sever dissociation, depersonalisation
    • Loss of consciousness(may be dangerous in certain situations)
    • Depression of heart rate and respiration. Especially when consumed with alcohol. If ketamine is taken with other stimulants such as ecstasy or speed, a rise in heart rate and blood pressure may occur. This can be dangerous to people with an underlying heart condition.
    • Heavy use of ketamine can cause long term damage to bladder and urinary tract. Sometimes users initially take more ketamine to numb the pain and discomfort caused by these problems but this makes it much worse in the long run.


* Much more common among first-time users

Dose and Onset

How? How much? When? For how long?

Read our section on dosing and tolerance in ME for more information.

As with any drug, the correct dose for you depends on factors such as weight, gender, metabolism, whether you have taken the drug recently or not, amongst many others.

How you take it matters...


Snortingis the most common way of using it. People usually divide the powder out into lines with a card and snort it with a straw or a piece of paper. Snorting through one nostril over a long time can lead to nasal ulcers or damage the septum.


Oral use of ketamine results in slightly different effects to snorting or injecting. If taken as a ‘bomb” (wrapping a dose in a cigarette paper) the effects take longer to feel and the experience will last longer. Taking ketamine orally usually results in a less intense experience. Gumming is another way of doing it. A small amount is applied on the inside of the lips or gum. This can damage your gums and lips. Gumming is not a common way of taking ketamine as most users find the taste very unpleasant..

Intramuscular injection

Injection is the most harmful way to take it. Like all other substances mentioned on website- it’s recommended that you do not inject ketamine. Injecting also increases the likelihood of becoming addicted to a substance.

How much?


  • Light dose: 15-30mg
  • Common dose: 30-75mg
  • Strong dose: 60-125mg
  • Heavy ("K-hole"): 100-250mg


  • Light dose: 50-100mg
  • Medium dose: 75-300mg
  • Strong dose: 200-450mg
  • Heavy ("K-hole"): 500mg+

Intramuscular injection

  • Light dose: 15-30mg
  • Medium dose: 25-50mg
  • Strong dose: 40-100mg
  • Heavy ("K-hole"): 60-125mg

Source: Erowid

When do the effects kick in and for how long?

The START time below is when you will usually begin to feel the effects of ketamine from the time when you first take it. The DURATION is roughly the length of time you will experience the effects, after which the effects will start to wind off and you might start to feel the calm-down/comedown down effects.

Timeline for snorted ketamine:

  • START: 5-15 minutes

  • DURATION: 40-60 minutes

  • AFTER-EFFECTS: 1-3 hours

Timeline for ketamine taken orally:

  • START: 5-20 minutes

  • DURATION: 90 minutes

  • AFTER-EFFECTS: 40-80 minutes

Timeline for injected ketamine:

  • START: 1-5 minutes

  • DURATION: 1-2 minutes

  • AFTER-EFFECTS: 2-4 hours

Ketamine may have an anti-depressive effect in low doses (20-30mg), and there are currently a number of ongoing research trials looking into this.

Sources: and


Ketamine interacts a lot with other substances. When taken with other depressants, such as opioids, it can increase their effects. As it can also increase heart rate and blood pressure, taking it with stimulants can result in heart palpitations.

+ ? =

dangerous to synergy bar


Click one of the drugs below and see how it mixes with .



Harm reduction

Head over to our ME section if you would like to know more about harm reduction.

Ketamine interacts a lot with other substances. When taken with other depressants, such as opioids, it can increase their effects. As it can also increase heart rate and blood pressure, taking it with stimulants can result in heart palpitations.




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Ketamine has a high potential for abuse and while it is not physically addictive, it can cause psychological dependence in some users. Tolerance to the effects of ketamine develops quite quickly, so user need to use more and more of the drug to get the same effects as when they started using.

Read more about dependence here.

When you want to quit

If you decide to stop using ketamine, you may experience some unwanted withdrawal effects. If you do, it is a good idea to speak to a health professional who will be able to support you and signpost you to helpful services.

Some of the withdrawal effects of ketamine may include:

Don't hesitate to look for medical help, you won't get in trouble. Talk to your GP, who will be able to refer you on to your local addiction service.

There are several advice services available online and over the phone including:

In the long term

Ketamine can have long term effects, both physically and mentally when consumed regularly.

Urinary problems

Long term use of ketamine can lead to urinary problems. In the most serious of cases, this may result in the removal of the bladder. If you use ketamine and experiencing any pain or difficulties in urinating, stop use immediately and seek advice from your GP. Some people take more ketamine to help with this pain, however this may cause further, more serious damage.

Long term memory problems

Ketamine has been shown to interfere with memory, learning and attention. Some users have also described having flashbacks after taking the drug.

Source: Jansen, K. L. R 1993. Non-medical use of ketamine. British Medical Journal, 306, 601-602.

The Law

Ketamine was reclassified to a Class B drug in the UK in 2014. The UK Advisory Council on the Misuse of Drugs made this recommendation based on the chronic harms associated with ketamine use.


  • Belgium: It is legal for medical and veterinary use and illegal when sold or possessed without a prescription.
  • Czech Republic:  It is legal for medical and veterinary use and illegal when sold or possessed without a prescription.
  • Denmark: It is legal for medical and veterinary use and illegal when sold or possessed without a prescription.
  • France: Ketamine is a Schedule IV drug.
  • Germany: It is legal for medical and veterinary use and illegal when sold or possessed without a prescription.
  • Norway: Ketamine is a Class A drug.
  • Slovakia: Ketamine is a Schedule II drug.
  • Sweden: Ketamine is a Schedule IV drug.
  • UK: Ketamine is a Class B drug.


  • Brazil: The drug is legal for veterinary use and illegal when sold or possessed for human use.
  • Canada: Ketamine is a Schedule I drug.
  • Mexico: Ketamine is a Category 3 drug.
  • US: Ketamine is a Schedule III drug.

Asia and Australasia

  • Australia: Ketamine is a Schedule IV drug.
  • China: Ketamine is a Schedule II drug.
  • Hong Kong: Ketamine is a Schedule I drug.
  • Malaysia: The possession and sale is illegal.
  • New Zealand: Ketamine is a Class C drug.
  • Singapore: Ketamine is a Class A drug.
  • South Korea: The possession and sale is illegal.
  • Taiwan: Ketamine is a Schedule III drug.


More information, references, useful links...


Is ketamine a horse tranquiliser?

Ketamine is used as a safe anaesthetic in humans and also in many animals- not just horses. When first developed, it was for humans and used in certain situations where it might not be practical to use other anaesthetics that depress breathing. It is widely used in medical emergencies as a painkiller or as an anaesthetic in developing countries.

If ketamine is used for medicine, then will it be safe for me?

Ketamine is used in medical settings as a safe anaesthetic and painkiller. However, recreational use may not always be safe. Medical ketamine will be pure, whereas street ketamine may contain dangerous adulterants. In a recreational setting, ketamine can make you feel detached from your surroundings. You may find it difficult to move, which may put you in a vulnerable position or lead to injury. Long term use can also have serious effects, including damage to the bladder and urinary tract.

Useful links

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