Abstract: The present invention provides a method for delivering a P methysticum extract to an animal in need thereof, the method comprising the steps of: (i) administering the P methysticum extract orally to the animal, and (ii) administering an effervescent agent orally to the animal to cause the generation of an effervescence product within the alimentary tract of the animal, wherein the P methysticum extract and effervescence product co-locate at a site in the alimentary tract of the animal such that a psychoactive effect of the extract is improved relative to a method whereby there is no co-location of an effervescence product and the P methysticum extract. The method may be useful in altering the neurological state of a subject, to decrease anxiety, increase relaxation, decrease wakefulness, increase happiness, increase cheerfulness, or improve cognitive ability.