Abstract
Recently, there is a global growing concern over the new (mainly synthetic) psychoactive substances, known as legal highs, research chemicals or bath salts. They are represented by various chemical groups imitating "old" illicit drugs with stimulant, euphoric, hallucinogenic or sedative effects.
In the Czech Republic, the peak of their use and supply was observed at the beginning of 2011, when new psychoactive substances were available in smart shops known locally as Amsterdam shops - in that time mainly synthetic cathinones and also synthetic cannabinoids were present. After legislative change that placed tens of new substances under the control of criminal law in April 2011, new psychoactive substances are available at Internet and their use is (after short and media driven boom in early 2011) rather limited and decreasing.
Though, the use of new synthetic stimulants was recently reported locally among problem (injecting) drug users; new very potent synthetic opioids represent potential threat of further expansion in this users' subgroup.