Leicestershire Police has arrested its first suspected dealer since so-called "legal highs'' were banned.
Officers detained the 27-year-old man in Leicester city centre today on suspicion of possession with intent to supply a controlled drug.
He was found to have a number of packets of what police believe to be synthetic cannabis and quantity of cash.
Officers then searched his home and found further packets of the suspected drug, with an estimated value of £250.
He was taken into custody and questioned on suspicion of committing an offence under the Psychoactive Substances Act 2016, which came into effect last month.
Earlier this year, a doctor told the Leicester Mercury he was concerned about the growing number of people using the substances.
City centre police have also reported a number of incidents in which users have exhibited wild and distressing reactions to the drugs - including one man they found licking a building's railings and others who imagined they were being attacked by flying objects.
The new law outlaws the possession, production, sale and importation of the chemicals, which typically come in the form of powders or smoking mixtures.
A number of shops which previously sold the substances have told the Leicester Mercury they have removed them from sale.
One handed police a £4,000 haul of the drugs within hours of the law coming into force.
Prisons inspectors have said the drugs are readily available and have contributed to violence and disorder among inmates.
Now, selling them will carry a maximum prison sentence of seven years.
Buying them online from an overseas retailer and having them posted to the UK would be classed as importation.
Giving a product to a friend would be categorised as supplying a drug.
Advice on the side effects of taking psychoactive substances and the new law are available at:
