We all know drugs are dangerous there have been number of studies to determine the drugs that are dangerous and few drugs have been legalized in some parts of the world because of its medicinal purpose. In the other hand there are drugs like cocaine and heroin that cause major effects on the human body and are very addictive. Few drugs due to over dosage can lead to death as well! Few drugs like LSD,Crystal Meth can cause serious mental damage.
Here are few most dangerous drugs that are know :
10. Marijuana
Cannabis, also known as marijuana among several other names, is a preparation of the Cannabis plant intended for use as a psychoactive drug or medicine.The main psychoactive part of cannabis is tetrahydrocannabinol (THC); one of 483 known compounds in the plant,including at least 65 other cannaboides.
Cannabis can be used by smoking, vaporization, within food, or as an extract.Cannabis is often used for its mental and physical effects, such as a “high” or “stoned” feeling, a general change in Perception, euphoria(heightened mood), and an increase in appetite.
9. LSD / ACID :

Lysergic acid diethylamide (LSD), also known as acid, is a psychedelic drug known for its psychological effects. This may include altered awareness of the surroundings, perceptions, and feelings as well as sensations and images that seem real though they are not.[It is used mainly as a recreational drug and for spiritual reasons. LSD is typically either swallowed or held under the tongue. It is often sold on blotter paper, a sugar cube, or gelatin. It can also be injected.LSD is not addictive.However, adverse psychiatric reactions such as anxiety, paranoia, and delusions are possible.
8.Amphetamine :

Amphetamine(Speed Drug) is a potent central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity. Amphetamine was discovered in 1887 and exists as two enantiomers.levoamphetamine and dextroamphetamine. Amphetamine properly refers to a specific chemical, the racemic free base, which is equal parts of the two enantiomers, levoamphetamine and dextroamphetamine, in their pure amine forms. The term is frequently used informally to refer to any combination of the enantiomers, or to either of them alone.
Historically it has been used to treat nasal congestion and depression. Amphetamine is also used as an athletic performance enhancer and cognitive enhancer, and recreationally as an aphrodisiac and euphoriant. It is a prescription drug in many countries, and unauthorized possession and distribution of amphetamine are often tightly controlled due to the significant health risks associated with recreational use.
7. Scopolamine

Hyoscine, also known as scopolamine, is a medication used to treat motion sickness and postoperative nausea and vomiting. It is also sometimes used before surgery to decrease saliva. When used by injection effects begin after about 20 minutes and last for up to 8 hours. It may also be used by mouth and as a skin patch.Common side effects include sleepiness, blurred vision, dilated pupils, and dry mouth. It is not recommended in people with glaucoma or bowel obstruction. It is unclear if use during pregnancy is safe; however, it appears to be safe during breastfeeding.
Hyoscine is in the antimuscarinic family of medications and works by blocking some of the effects of acetylcholine within the nervous system. Under the influence of this drug, users lose all sense of self-control and become incapable of forming memories. It induces hallucinations at a low dosage and can disrupt normal brain functioning at higher dosages.
6. Ketamine

Ketamine, is more commonly known as horse tranquilizer, but was first developed for human use. Ketamine, sold under the brand name Ketalar among others, is a medication mainly used for starting and maintaining anesthesiaIt induces a trance-like state while providing pain relief, sedation, and memory loss.
Other uses include for chronic pain and for sedation in intensive care.Heart function, breathing, and airway reflexes generally remain functional.[5] Effects typically begin within five minutes when given by injection with the main effects lasting up to 25 minutes.
5. Krokodil

Krokodil is a Russian drug which is on the rise right now. It is believed that around one million Russians are addicted to this drug, possibly because it is homemade and thus widely available. It attracts users by its extremely low prices, but is often much more dangerous because it is made by unprofessional persons.
It is thrown together using ingredients like painkillers, iodine, lighter fluid and industrial cleaning agents. This chemical makeup makes the drug highly dangerous and is likely to cause gangrene and eventually the rotting away of flesh.
4. Opiates

Opiates are alkaloid compounds naturally found in the opium poppy plant Papaver somniferum.The psychoactive compounds found in the opium plant include morphine, codeine, and thebaine . The side effects of this drug include sedation, respiratory depression, constipation and a strong sense of euphoria.
Morphine is often legally prescribed to reduce pain and due to its addictive nature is only administered in hospitals. The usage of this drug can cause nausea and vomiting, drowsiness, itching, and a hormone imbalance which might lead to malfunctioning of reproductive systems.
3. Crystal Meth

Crystal meth or methamphetamine has been around since the 19th century and was apparently used as a stimulant by Nazis. It then reappeared in the 1950s in the US, marketed as an anti-obesity drug. Meth is highly addictive and also equally dangerous for your health. In low doses, methamphetamine can elevate mood, increase alertness, concentration and energy in fatigued individuals, reduce appetite and promote (initial) weight loss.
At higher doses, it can induce psychosis, breakdown of skeletal muscle, seizures and bleeding in the brain. Chronic high-dose use can precipitate unpredictable and rapid mood swings, prominent delusions and violent behavior.Meth also causes skin conditions such as acne and chronic tooth decay which is a combination of dry mouth and lack of oral hygiene.
2. Heroin

Heroin is the most dangerous drugs in the world and it is responsible for thousands of death every year. Heroin, also known as diamorphine among other names, is an opiate most commonly used as a recreational drug for its euphoric effects.Medically it is occasionally used to relieve pain and in opioid replacement therapy. Heroin is typically injected, usually into a vein; however, it can also be smoked, snorted or inhaled. Onset of effects is usually rapid and lasts for a few hours.
Common side effects include respiratory depression (decreased breathing) and about a quarter of those who use heroin become physically dependent. Other side effects can include abscesses, infected heart valves, blood borne infections, constipation, and pneumonia. After a history of long-term use, withdrawal symptoms can begin within hours of last use.When given by injection into a vein, heroin has two to three times the effect as a similar dose of morphine.It typically comes as a white or brown powder.
1. Cocaine
Cocaine, also known as coke, is a strong stimulant mostly used as a recreational drug It is commonly snorted, inhaled as smoke, or as a solution injected into a vein. Mental effects may include loss of contact with reality, an intense feeling of happiness, or agitation. Physical symptoms may include a fast heart rate, sweating, and large pupils. High doses can result in very high blood pressure or body temperature.Effects begin within seconds to minutes of use and last between five and ninety minutes.
Cocaine has a small number of accepted medical uses such as numbing and decreasing bleeding during nasal surgery.Despite being glamorized by celebrities, and popularly used by people with lavish lifestyles, cocaine is a very commonplace drug. Some of the side effects of cocaine include liver, kidney and lung damage, and permanent damage to blood vessels, which often leads to heart attacks, strokes, and ultimately death. It has been banned by several countries due to the high number of deaths caused by it.