The new issue of Erowid Extracts has article on this fascinating topic:
Parker RC, Lux. "Psychoactive Plants in Tantric Buddhism; Cannabis and Datura Use in Indo-Tibetan Esoteric Buddhism." Erowid Extracts. Jun 2008;14:6-11.
Parker RC, Lux. "Psychoactive Plants in Tantric Buddhism; Cannabis and Datura Use in Indo-Tibetan Esoteric Buddhism." Erowid Extracts. Jun 2008;14:6-11.
Quote“This article represents a fairly comprehensive survey of references to datura and cannabis in Indo-Tibetan tantric Buddhist texts that have been translated into English.
…
Although interesting speculative work has been written on the subject, a focused analysis of explicit textual evidence has not been published. Over the last few decades, university religious studies departments have produced translations of Buddhist tantric texts of unprecedented quality, providing ample material for an examination of psychoactive plant use by Buddhists in Asia. This article considers some of the evidence with respect to tantric Buddhism in India and Tibet, focusing on the use of cannabis and datura.â€