Today, there are countless examples of illegal drugs that seem to be 'fashionable'.
With many seemingly harmless drugs out there, the fact is they are more likely than not illegal for a reason.
From prescription products that people take recreationally to more serious things, illegal drug use is a common problem and it's also a dangerous one.
Typically, in many countries illegal drugs are split into various categories with differing levels of severity depending on how addictive the drug is and also how dangerous it is.
Some examples of the most dangerous drugs out there would be heroin, cocaine, amphetamines, barbiturates, LSD and also MDMA (ecstasy) and finally cannabis.
While there are countless illegal drugs, these are perhaps the most well-known of the lot.
Depending on where one lives, some drugs might even be legalized, or at the very least, tolerated as in the case of cannabis in some locations.
In 1948 a unilateral United Nations agreement on narcotics was reached making most drugs that can be used recreationally illegal.
The list includes cannabis, cocaine, MDMA, Ephedrine, Ketamine, Heroin, amphetamines, methamphetamines, barbiturates and their derivatives.
It's also true to say that perhaps many of the world's illegal drugs aren't as dangerous as alcohol and tobacco which is perhaps the world's most dangerous two drugs and in fact the two that contribute to many, many deaths and terminal illnesses each and every year.
The main difference between the legalized recreational drugs (tobacco and alcohol) and the illegal ones mentioned above are that illegal drugs tend to be completely unregulated and also they do a great deal more damage over a short period of time.
Hallucinogens or psychotropic (mind altering) drugs have been seen by many as a harmless category of drug.
This group which includes magic mushrooms, LSD, Acid, Ketamine (a horse tranquilizer) and even cannabis at times can significantly alter one's state of mind making things seem real when in fact they are not.
While it's true they have been used by native tribes and other cultures, in an uncontrolled and recreational situation - they can be devastating.
One example would be mistakenly believing that one could fly, then jumping off a bridge to prove that theory.
Opiates are perhaps the most dangerous due to the combined effects that this group of drugs have.
With hallucinogenic properties as well as being highly addictive, often it takes just a single dose to become hooked.
Side effects include reduced brain functions and also the fact that over time, it takes more to enjoy the same level of temporary euphoria.
Amphetamines, barbiturates and other drug classes are just as dangerous, and many studies have proven that even highly popular recreational drugs such as MDMA and cannabis have many, many risks.
From addictive qualities to increased susceptibility to psychosis, when looking at what are illegal drugs, it's true to say that they are indeed illegal for a reason.