The dangers of using a herbal tea with other substances were spelled out by a coroner in the Republic of Ireland yesterday following the death of a young man who bought products on the internet.

Cormac O'Sullivan (21) was rushed to hospital after his brother Fionnan noticed he had stopped breathing.

He had earlier been snoring loudly while sleeping on the couch of his home at Park Lane, Dun Laoghaire, Co Dublin, in the early hours of May 10, 2009.

He was pronounced dead soon after arriving at St Vincent's Hospital.

Drugs and plant-like material were found at the scene and police found a large number of envelopes from all over the world for various herbal suppliers.

Coroner Dr Brian Farrell recorded a cause of death by cardio-respiratory failure due to the combined toxic effects of a combination of carisoprodol -- which is used for the relief of muscular and skeletal pain -- sedative drugs, and mitragynine, which is an ingredient of Kratom tea.

Kratom tea is recognised and used by people for relaxation purposes, the inquest heard.

But Dr Farrell said caution must be exercised when adding other substances or medications to it.

"It ought not to be used in combination with other medications," he said. "People need to be aware of the potential results of using Kratom tea, especially with other medications.

"Cormac's tragic death emphasises the need for prudence when using herbal substances. Buying them on the internet doesn't guarantee their quality or content," he said.

The inquest heard that Mr O'Sullivan had done a lot of research on the substances.

"Unfortunately, that combination was capable of causing cardio-respiratory failure. It was a risky venture," Dr Farrell said.

In a statement read into evidence at the inquest at Dublin City Coroner's Court yesterday, Mr O'Sullivan's brother Fionnan said his brother would blend up Kratom, and possibly opium, into a tea.

"He liked to make these teas as they relaxed him," he said.

"He was quite confident in what he was doing. He had also researched what to do if he had an adverse reaction to teas and drugs," said Fionnan.

He was aware that Cormac, who worked with a group which developed games for the Wii and loved his job, got herbal substances on the internet through the packages that would come to the house.

Dr Farrell recorded a verdict of death by misadventure and expressed his condolences to his brother and family.