10 of the Most Dangerous Drugs

There have been any number of studies on what might be the world’s most dangerous drugs over the years. A problem many of these have is they focus on only one aspect of what makes any particular drug harmful. For example, how much damage to society does it cause, is it dangerous in the long term / short term, or how addictive is it. To really get to grips with this question all these factors need to be taken into account; but also we need to look at the actual statistics – how many people are actually seriously harmed by these drugs.

The first thing to do is forget any government classification of narcotics. These are partly driven by vested interest, partly by politics and often out of date with the reality on the street. It was the chief British drugs advisor, Prof. David Nutt, who pointed out that horse riding was statistically far more dangerous than taking ecstasy. However, one is a highly illegal drug whereas the other is considered a wholesome pursuit. So, this would lead me to think that it isn’t our governments concern for our safety that drives their drug policies.
Perhaps the most glaring inconsistency in almost any government’s ability to rank the danger of drugs is the fact that the only two that kill in their millions are perfectly legal whilst some schedule 1 / class A drugs are not toxic or addictive.

In this list of the 10 most dangerous illicit drugs I am going to focus on the danger the drug presents to the user. So I’m looking at how toxic the drug is, how addictive it is and how quickly you will cease to be a functioning human being once you start using.

10. Ketamine


Ketamine in powder form

AKA: K, Special K, Vitamin K, K2

Price: $$$

Ketamine is perhaps best known as a horse tranquiliser although it was developed for human use. It was intended to replace PCP (Angel dust) as a shorter lasting anaesthetic and it is still used in certain situations. However, there are several side effects that come in to play as the drugs effects wear off, most notably hallucinations. These usually last less than 2 hours along with feelings of detachment, which can be fairly extreme.

Ketamine overdoses are potentially fatal and there is no effective antidote. A patient may need to be put on life support to maintain respiratory function until they can breath on their own. Possibly the greatest risk to users of ketamine though is the direct psychological effects or the “K-hole”. The user may become so detached from reality that they endanger themselves. For example two eminent ketamine experimentors wound up dead, one from hypothermia and the other drowning.

There is plenty of evidence of ketamine being addictive and once this happens tolerance soon builds up. Along with this go several side-effects such as bladder problems, memory loss and various other psychological impairments. Withdrawal may result in minor, but permanent nerve damage.

9. Amphetamines

Snorting amphetamines

Snorting amphetamines

AKA: Speed

Price: $$

It may seem strange but one of the few legitimate medical uses of the stimulant amphetamine is in the treatment of attention deficit hyperactivity disorder (ADHD). For most people though, the effects of taking amphetamines are feeling energised and confident.

There is a risk of addiction, but the evidence is that this is only particularly likely with heavy use. If someone does become addicted then tolerance grows quickly requiring ever increasing doses. Surprisingly amphetamine overdoses rarely prove fatal and there is little evidence to show that it can result in heart attack, strokes or other cardiovascular events.
What excessive doses can do is effectively change the wiring of the brain making addiction stronger or more likely.

Perhaps the best known and most sinister of amphetamines side effects is “speed psychosis”. One study found that nearly 20% of heavy users had clinical levels of psychosis. Of these up to 15% never fully recover. The symptoms of amphetamine psychosis are very similar to schizophrenia with hallucinations, delusions of persecution and extreme agitation being common.
And this is why amphetamines make it onto this list.

8. Benzodiazepines


Temazepam – a benzodiazepine

AKA: Benzos, downers, duck eggs

Price: $

Valium (diazepam) is probably the best known of all prescription sedatives. They were developed partly in an effort to replace barbiturates (see below) as an anti-anxiety/depressant. Whilst they are somewhat less likely to result in fatal overdose they are highly addictive. Benzodiazepines are also widely available, this has made them the most widely abused class of psychoactive drugs in America.

Much of the misuse of benzodiazepines revolve around managing other drug use, e.g. to make heroin or amphetamine come downs more tolerable. Whilst there is evidence of benzodiazepine addiction alone most users seem to have a multi-drug problem.

What is interesting about this class of drug is the problematic behaviours caused are exactly the opposite you would expect from a drug considered a sedative. For example in the 1990s in the UK, at the height of the ecstasy-fuelled rave scene there was more violence surrounding the use and supply of the benzodiazepine tamazepam than all the other party drugs together.
The same appears true for users. In what are termed paradoxical effects people using these drugs may end exhibiting symptoms the very opposite of those the drug is intended to treat. These symptoms often include psychosis and higher levels of psychopathy. Studies have also shown use of benzodiazepines increases risk taking behaviour.

7. Methadone


Methadone – © Fred Shakeshaft


Price: $$

6. Barbiturates


Prescription barbiturates

AKA: Downers, red devils, pink ladies, purple hearts, goofballs

Price: $

Barbiturates have been around for a long time and were once the drug of choice of the American housewife. They are a class of sedatives which were widely prescribed to treat depression, anxiety and even sleeping problems until the potential dangers were realised in the late 1960s. Since 1970 barbiturates have not been freely available, if they were they would appear higher up this list.

The drugs work by depressing the nervous system which in turns gives the user a feeling of relaxed contentment and even euphoria. They also reduce anxiety and inhibition, somewhat similar to the effects of alcohol. There is no lack of evidence to show the addictive powers of barbiturates and this is both physical and psychological. In fact barbiturate withdrawal is one of the most severe and can be fatal.

The true danger of barbiturates though lies in the ease in which users can overdose. There is a much finer line between a normal and a deadly dose than with most other narcotics. Over the years countless deaths have been attributed to accidental barbiturate overdoses including celebrities such as Marilyn Monroe and Jimi Hendrix. However, even in “safe” doses barbiturates can eventually kill you with a range of physical and mental side effects.

5. Tobacco

Smoking tobacco

Cigarettes, the world’s most popular way to kill yourself!

AKA: Snout

Price: $

If anything else killed up to 20% of the population prematurely then you might expect the government to frown on it. But here we have a highly addictive drug that causes the slow painful death of millions worldwide every year and it is perfectly legal. It does make you wonder about the authorities motivations for controlling other drugs though.

But everybody knows smoking kills you so we’ll move on.

4. Alcohol


Hard liquor – © The D

Price: $

The fact alcohol is legal in most countries is the main reason it is not higher up the list. There is little doubt that alcohol addiction will mess you up but the fact it is legal means many can just about hold things together and put on a veneer of normality. That is until their liver gives up and everyone close to them leaves.

3. Crystal Meth

Crystal meth

Crystal meth – methamphetamine © Radspunk

Price: $$$

Methamphetamine, or crystal meth, has actually been around since the 1890s. Its first recorded use was by the Nazis in World War II, when it was used as a stimulant by fighter pilots and tank commanders. The drug then reappeared in 1950s America as an anti-obesity product. Remember those diet pills you heard about people getting addicted to – crystal meth!

These days methamphetamine has a very different reputation. If you believe the media there is a a veritable epidemic of crystal meth has swept across the U.S. turning users into skeletal zombies within a matter of weeks. Although this is certainly not what happens to everyone who tries methamphetamine it is one of an elite class of drugs where there is virtually no bottom to how bad it can get.

Whilst in some ways similar to other amphetamines crystal meth is both more addictive and much worse for your body. The effects of crystal meth are likened to crack cocaine, but lasting much, much longer.
However, methamphetamine is a neurotoxin; it works by flooding the brain with  high levels of dopamine which creates the feelings of euphoria. Ironically it also damages the dopamine receptors meaning you will need ever increasing doses of meth and leading to long term emotional problems. There is also evidence of that long term meth use destroys the brain’s grey matter.

Methamphetamine is known to be an aphrodisiac and can prolong sexual activities. It is not unheard of for meth-fuelled sex parties to go on for days. On the negative side, a direct correlation between high-risk sexual practices and related infections has been seen with crystal meth abuse.

One of the best known side effects suffered by meth addicts is what the drug does to the skin. The drug itself causes skin conditions such as acne which are compounded by the lifestyle and lack of personal-care. This is further compounded by addicts often compulsively and obsessively picking their skin of their face causing open sores. The other classic result of meth abuse is “meth mouth”. This chronic tooth decay is the combination of a dry mouth and the complete lack of oral hygiene when addicts become totally self-neglecting..

Along with all the meth specific risk are several common to other drugs. There is psychosis, risk of heart attack or stroke and possible death by overdose. This combined with the fact most addicts will need to resort to crime to pay for their habit is why crystal meth features on our list.

2. Heroine

Heroine cooking

Cooking up some heroine

AKA: H, junk, horse, smack, skag, brown

Price: $$$

It was a difficult choice between heroine and crystal meth but from what I’ve read heroine wins out on the most dangerous drugs stakes. There are three main reasons for this the first of which is heroine is just more dangerous. Whilst taking too much meth might not do you any good it is a lot more difficult to kill yourself with an OD than it is with heroine. In fact it is all to easy to accidentally overdose on heroine. One reason is it doesn’t take that much, but the main reason is that no one has a clue how pure the stuff you get on the street is. Every set of hands it passes through it gets cut with some other dirty white powder. Until that is, one day you get some that is 50 or 60% pure. This might contain three or four times the dose you’ve been taking and that’s enough to kill you.

Then there is the physical withdrawal. Once addicted kicking the habit is going to involve a whole world of pain. Whilst generally no worse than a case of flu this can be more than enough to discourage the addict to try quitting. Of course stopping using is also going to involve dealing with the psychological addiction too. So heroine is probably the hardest of all drugs to give up.

One of heroine’s worst attributes is the drug’s ability to practically take over a user’s soul so that nothing else matters. None of the other drugs at the top of this list will sap the life out of you quite like heroine. It will be the only thing you think about from the moment you wake up and junkies will do anything just to get the next fix.

1. Cocaine

Crack cocaine

Crack cocaine

AKA: Coke, blow, charlie, crack, rock

Price: $$$$

Cocaine may be regarded as the champagne of drugs by some, and the price tag reflects that. However, I wouldn’t take the price of any of these drugs too seriously. At the end of the day, once you develop a serious addiction to any of the top three, it will cost you all your money, and probably your soul too!

Despite having the status of the celebrity drug of choice, as used by models, rock-stars and Wall Street traders, cocaine is surprisingly commonplace. One study suggested nearly 10% of young adults in the U.S. had used cocaine within the last year. With effects including a sense of euphoria, limitless energy and god-like feelings why wouldn’t it be popular?
But unsurprisingly it is highly addictive. Coke acts on the primal reward areas of the brain which are normally triggered via, for example, sex or eating food we like. This makes the cravings for cocaine powerful.

As well as being bad for your wallet cocaine is particularly bad for you with more emergency room visits in the U.S. being caused by it than any other illegal drug. There are few parts of the body cocaine does not adversely effect but the most significant risks are sudden death from heart attack or stroke.

Whilst the physical effects of withdrawal are relatively minor the psychological addiction can be hard to break with some users even becoming suicidal. Although the process may only last 2 weeks a cocaine addict may experience cravings for the drug years down the line.

Of course the powerful effects of cocaine weren’t quite enough for everyone. Although you can inject coke, it is dangerous and apparently gives a very strong but short-lived rush. This is why crack came about. You can’t effectively smoke coke but this is how you take crack. The result is a more powerful but shorter lived hit, followed by a nasty come down. This makes crack even more addictive than normal cocaine.

Crack has all the same risks as other forms of cocaine plus smoking it is very bad for your lungs. There is also a higher risk of overdosing due to increased cravings.


In conclusion; there are some drugs that people can live with, some for a long time. These may be legal or illegal and how long you live a relatively healthy life on these is somewhat of a lottery. There are however some drugs that even if you have all the money in the world and a guaranteed pure source are still going to mess you up. Take your pick from crack, meths, heroine or alcohol – if you have an addictive personality type then it probably won’t end happily.


  • George

    seriously? i cant believe you have cocain over krokodil. actually, you dont even have krokodil. its obvious you researched this a lot…

    • surfgatinho

      I did think about krokodil, but decided its use (outside Russia) was pretty limited. As the article is taking into account the social damage, as well as bodily damage, I didn’t include it.
      That said, the list ins’t quite finished and I may change it at some point…

      • Andrew

        Heroin is. The most hardest drug to come off I no 30 years on it an am still battling with it

  • Lowne Wolfe

    Wrong, ketamine is NOT called k2. K2 and Spice were brand names of products which, in earlier formulations, mimicked cannabis as they activated THC receptors. It was intended to be used as a research chemical and never to be ingested by humans. The K2 brand is no longer sold. K2 is now the street name or slang term for similar products. Each year the current formulation was made illegal, jwh-018 and jwh-073 being the earliest. It is made by spraying the chemical on dried herbs which the user then smokes or vapes. It is sold as “incense” and illegal in most states but not all as the packages say “not for human consumption”. Unlike earlier formulations (which are now all illegal and class I drugs) the latest formulation (am-2201) has been causing kidney failure and digestive issues in MANY MANY users, it has killed many people as well. I can personally attest to k2’s affects, lost kidney function for 2 months myself and I got VERY lucky I didn’t die. But again, ketamine is not called k2.

    • surfgatinho

      You’re right. I’ll fix it when I get round to finishing this article off properly.

  • Misanthropia

    This is why women shouldn’t be housewives or they’ll start taking drugs out of boredom LOL

  • Tom

    This list is pretty ridiculous. There are a LOT of errors. I would know, having been addicted at one point or another to a few of these.

    The Cocaine entry at the top of this list is ridiculous!
    Why Barbs are priced at 1dollar, given that it would cost a FORTUNE to get hold of them if you even could.
    Also, “The first thing to do is forget any government classification of narcotics”. Narcotics actually refers to a specific class of drugs, sedative analgesics…opioids/opiates. This belies the fact you aren’t well-researched in this area – rookie error…
    “Ketamine overdoses are potentially fatal and there is no effective antidote” – Ketamine is one of the safest drugs in terms of overdose! Of all ones to pick for overdose harm! The recreational dose is a tenth of the anaesthetic dose and you would pass out quite healthily before getting enough Ket in your system to overdose. The risk of Ket is when you hole in an unsafe environment.
    Let’s not forget that you neglected:


    You shouldn’t put content out there that is incorrect…it leads to misunderstandings for people believing inexperienced, poorly researched articles. You are doing damage!

    • Just Me

      Tom, rather than creating even more entries for more types of drugs, it makes more sense to group similar drugs together:

      Opioids, such as heroin, methadone, fentanyl, krokodil, etc.

      Stimulants, such as speed, crystal meth, cocaine, flakka, etc.

      Putting drugs like speed and crack different classes with different dangers is like creating a separate category for beer, wine, vodka, and Everclear. Sure, Everclear is more dangerous than beer, but it’s still all the same drug.

      You do have a few important ones on your list which don’t fall into any convenient categories, like Datura and PCP. It’s good not to overlook those, so good catch.

  • Blade2001

    Kroiodil and bath salts are way more dangerours

  • Михаил Отте

    My top 5:

    1. PCP
    2. Datura/Anti-Cholinergics
    3. Meth
    4. Barbituates
    5. Heroin

  • Chowderbatter

    Is there a reason heroin is spelled with an E in this article?

    Also, I’d say tobacco and alcohol have to easily top any list of most deadly. They may or may not be as addictive as other more “dangerous” drugs, but they are so common, so pervasive, and they directly impact non-users in a way that all of the others combined do not. Second hand smoke inhaled by children, family, co-workers, passersby. Alcohol related abuse and fatalities.

    All other drugs combined do not do as much damage as either one of those two alone. It’s not close. And everyone on the planet knows alcohol and tobacco addicts.