A man has died after taking the illegal psychoactive drug known as Black Mamba, police said.
Officers were called at 19:40 BST on Saturday to an address on London Road, Nottingham.
A 37-year-old man was pronounced dead, while a man, 39, was taken to hospital in a non life-threatening condition.
Nottinghamshire Police said: "Initial investigations indicate the men had been taking the synthetic cannabinoid drug."
Police warned people of the dangers of Black Mamba, which leaves people in a zombie-like state.
Forensic examinations were still being carried out, the force added.