RT Journal Article SR Electronic T1 Herbal mind altering substances: an unknown quantity? JF Emergency Medicine Journal JO Emerg Med J FD BMJ Publishing Group Ltd and the British Association for Accident & Emergency Medicine SP 253 OP 255 DO 10.1136/emj.2003.005751 VO 21 IS 2 A1 C Doughty A1 A Walker A1 J Brenchley YR 2004 UL http://emj.bmj.com/content/21/2/253.abstract AB