WELLINGTON -Alexander the Great built a legendary empire before his untimely - and mysterious - death at the age of just 32 in 323 BC. Some historians argued were death was due to natural causes, while others maintained he was secretly murdered at a celebratory banquet. Now, an Otago University scientist may have unraveled the case some 2000 years later.

National Poisons Centre toxicologist Dr Leo Schep thinks the culprit could be poisonous wine made from an innocuous-looking plant, according to a report in the New Zealand Herald. Dr Schep, who has been researching the toxicological evidence for a decade, said some of the poisoning theories - including arsenic and strychnine - were not plausible.

Death would have come far too fast, he said. His research, co-authored by Otago University classics expert Dr Pat Wheatley and published in the medical journal Clinical Toxicology, found the most plausible culprit was Veratrum album, known as white hellebore. The white-flowered plant, which can be fermented into a poisonous wine, was well-known to the Greeks as a herbal treatment for inducing vomiting.

Crucially, it could have accounted for the 12 torturous days that Alexander took to die, speechless and unable to walk. Other suggested poisons - including hemlock, aconite, wormwood, henbane and autumn crocus - would likely have killed him far more quickly. Dr Schep began looking into the mystery in 2003 when he was approached by a company working on a BBC documentary.

‘They asked me to look into it for them and I said, ‘Oh yeah, I’ll give it a go, I like a challenge’ - thinking I wasn’t going to find anything,’ he said. ‘And to my utter surprise, and their surprise, we found something that could fit the bill.’

Dr Schep’s theory was that Veratrum album could have been fermented as a wine that was given to the leader. It would have tasted ‘very bitter’ but it could have been sweetened and Alexander was likely to have been very drunk at the banquet. But whether Alexander was poisoned is still a mystery. We’ll never know really,’ Dr Schep concluded.