Sussex University student Hester Stewart died after taking GBL
The dangers of "legal highs" and their increasing popularity among clubbers and festival-goers will be the focus of inquiries by government drugs advisers.
Dealers avoid drug laws by selling the herbal or chemical pills which are not currently classed as illegal.
The Advisory Council on the Misuse of Drugs is to investigate the chemical compounds of these substances to assess the harm they can cause.
Among the drugs already being examined is Spice, a type of synthetic cannabis.
The council says it is advising the home secretary about the drug, which some researchers believe contains an active ingredient 10 times stronger than its equivalent in cannabis.
Within the last year, the government has accepted the council's recommendations relating to "party drugs" GBL and BZP.
It intends to ban them after they were linked to the deaths of two youngsters.
Last week, an inquest found that one of them, Brighton medical student Hester Stewart, 21, had died in April as a result of taking GBL while drinking.
Council chairman Professor David Nutt said: "One of our key priorities for the coming year will be investigating the increasing threat of legal highs.
"It is important that we remain at the forefront of managing these emerging trends and the harms of substance misuse.
"We need to get across that some of these legal highs pose a real danger."
Trends among poly drug users - those who take a combination of drugs such as alcohol, cannabis, cocaine and ecstasy - will also be investigated.
Prof Nutt said scientific evidence relating to the drugs would allow ministers to legislate.
The council also intends to improve "early warning mechanisms" used to detect potentially harmful new drugs.