Between 2005 and 2013 there have been more than 100 deaths globally.
Deaths aren't often caused by overdosing, but ketamine can be a catalyst for drownings, traffic accidents and suicides. It can cause abnormal heart rhythms, nausea and even respiratory problems.
According to the Good Drugs Guide, ketamine makes talking, moving and even going to the toilet difficult.
"At high doses, ketamine can be physically incapacitating, even paralysing," the Good Drugs Guide says.
"Using this drug can make the user feel cloudy. It's been described as a disconnection between the mind and the body. If the dosage ingested is high enough, the user may lose consciousness.
"After use, a ketamine user may experience unusual dreams. He or she may also find that thought processes are cloudy. Thinking clearly can be difficult, and can lead to the user harming him or herself. The person who uses ketamine is at a higher risk for being involved in an accident than a non-user."
According the Good Drugs Guide, ketamine becomes a club drug when it is mixed with alcohol and could cause people to become aggressive.
It's an odourless and tasteless drug and it has been used as a date rape drug like GHB.
"The victim would likely remain conscious after ingesting the drug. He or she would appear intoxicated, and people nearby may assume that the person is drunk," the Good Drugs Guide said.
"The victim will not be aware of the fact they have been drugged and will have little or no recollection of the sexual assault itself."
Ketamine can also result in a user having a bad trip, causing mood swings and irrational behaviour.
A man described his experience with ketamine on education and harm reduction website Erowid.
He had a bad trip and felt he would be stuck in it forever.
"I have no concept of love, which, considering my girlfriend of a year was in the room is a bad thing. I am not in my body. I have no concept of friendship. I am struggling to remain conscious, because I am convinced that if I fall unconscious, I will never wake up," he said.
"My parents are going to find me in a mental hospital."
As he began to come around, he said he simply felt like he had been tranquillised.
Louise Cattell is one woman who was killed after she took ketamine in 2011.
According to the Hackney Gazette, the 21-year-old fashion worker tragically drowned in the bath in her Upper Clapton apartment, in the London Borough of Hackney, after taking ketamine.
Dr Selena Lynch said in the coroner's court during an inquest into her death that young people knew the risks and consequences but never thought it would happen to them.
"Ketamine is a particular risk because it is unpredictable. Like some other drugs of abuse it is very difficult to know what the consequence might be. In this case a young woman has lost her life and her family are bereft," she said.
The Hackney Gazette reported Ms Cattell's parents, Ross and Vicky, have fought to raise awareness of the dangers of ketamine.
"This is a drug that is taken by hundreds of thousands of people according to statistics, many of whom regard it as relatively safe," they said in a statement.
"We hope that by telling people about ketamine they will see that it is far from harmless.
It is not only addictive but can cause permanent damage to the brain and other organs like the bladder.
"It may be cheap and easy to get hold of but does that really make it worth the risk of not being able to get or hold down a decent job or spending the rest of your life through a plastic tube?"
