Yage is a native preparation from South America, with a widespread use in other continents. It commonly contains B. caapi and P. viridis, whose combination produces an increased state of alert, visions, hypersensitivity and a sense of transcendence, affecting the functioning of raphe neurons and of the locus coerulea, it does not produce addiction. Man and animals are phylogenetically linked, particularly in the use of psychoactive plants. But man, due to his complex brain structure and function, with a greater wealth of evolutionary possibilities towards higher levels of cognitive skills and complex learning, and advancing philo and ontogenetically, until reaching a cortical development such that it allows the specie to develop self-control and control of the environment; autonomy in decisions; inhibition of interfering responses, planning and goals; resolution of ethical dilemmas and access to abstract thinking. Man’s neural plasticity allows him to modify behaviors for the sake of his physical and mental health, by means of activities such as meditation, which produces feelings of transcendence as those related by some yage consumers. Can the two states mentioned have that similarity? Can they have the same impact on thoughts, feelings and actions? Can yage be used as physical, mental, emotional and spiritual therapy, without adverse effects? Key words: Yage, cognition, executive functions, learning, higher mental abilities.