TWO men are dead after using "herbal tea" - illegal synthetic cannabis.
Police and Queensland Health authorities are warning drug users not to take drugs containing synthetic cannabinoids, saying it is a poison.
A 41-year-old man, who had been on life support in Mackay Base Hospital's intensive care unit, died last night.
Police are investigating his death and that of a 33-year-old man who died at a residence on the north side of Mackay on Tuesday.
They believe the 41-year-old had been smoking the synthetic drug Full Moon.
The drugs are suspected because of packaging found near the two victims, who are known to each other.
Mackay Hospital and Health Service executive director of clinical services Dr David Farlow said the men's deaths were an "absolute tragedy".
Dr Farlow said the drug was "poison" and could cause brain damage, and the hospital was now treating, on average, one patient a day who was ill after taking very dangerous synthetic drugs.
Synthetic cannabinoids are heavily modified versions of the active compounds in the cannabis plant.
"The drugs can cause neurological symptoms, hallucinations and psychotic episodes," Dr Farlow said.
Detective Inspector Sam Bliss speaks about drug raids in Mackay: A search warrant was executed on the Love Heart Adult Shop and Sweet Cheeks Adult Shop yesterday as a result of police investigations. Detective Inspector Sam Bliss said police seized suspected synthetic drugs and equipment.
"And pre-death it tends to be multiple seizures.
"It's fast-acting, within seconds or minutes, as most of the time it's inhaled and gets into the bloodstream immediately," he said.
Formal toxicology tests are being done on the deceased men and police will do forensic tests to confirm the drugs' presence.
A search warrant was executed on the Love Heart Adult Shop in Mangrove Rd yesterday as a result of police investigations.
Detective Acting Inspector Sam Bliss said police seized suspected synthetic drugs and equipment.
She said although people can purchase the drug materials over the internet or in suburban shops, this did not make it legal or make them harmless.
"The chemical compounds found in these drugs are dangerous and are not herbal or natural alternatives to real drugs. They contain synthetic compounds which are toxic and extremely dangerous."
It was an offence to possess, produce, supply or traffick in such synthetic products, she said.