Derived from the bark of the Coryanthe yohime, the yohime tree of Central Africa, yohimbine is recognised as an aphrodisiac. The catch is that doses sufficient to cause stimulation are toxic. Yohimbine is also known as "Japanese Chocolate."
Two years after the Bogle-Chandler deaths, Dr Pang Teng Cheung, Director of Forensic Medicine for the Hong Kong Police, and an expert on Eastern drugs, reported two cases showing identical symptoms and death. They had taken yohimbine. Bogle and Chandler could conceivably have ingested yohimbine, overdosed, and died.
Other speculation: