Traditional usage – which can be many centuries old - is considered in Western medicine as not sufficient for safe application of these natural remedies. Most often, strict scientific validation is required specially when a new drug preparation is proposed to other people living in a completely different context. During this transition phase, many shortcuts can occur, the consequences of which can be a disaster! Ayahuasca, as first example, has been known since the beginning of the 19th century to science. This hallucinogenic decoction has been used traditionally for several centuries by South American Shamans of the Amazon region. Made from a unique combination of several tropical plants, this bitter drink is considered as an effective medicine both used to diagnose and treat disease. Actually, its basic chemical constituents – psychoactive tryptamines and beta-carbolines - are well characterized but the pharmacology of the brew is not yet completely understood. Over the last decade, its original native use has spread not only among mestizos population all over the Amazon area and several “churches” in Brazil, but also among few Western psychiatrists in the hope of treating dependence on drugs. Recently, its use has spread between “psychonautes” with much adaptation and changes compared to its original ritualistic use. For example, new plant admixtures growing in the temperate zones have been suggested to replace the original tropical ones that are difficult to obtain outside the Amazon. Their selection was made on a rapid phytochemical survey without any knowledge concerning their toxicity. Safety put apart, such proposal contradicts any sound ethnopharmacological behaviour as it negates the crucial importance of the ritual settings. The second example deals with the zombification process of the Haitian peasant folklore. Induced by the application of a powder containing tetrodotoxin from globefish species as main toxic ingredient, this extra-ordinary transformation attracted contra-productive publicity from the media. Many sensational articles were published in the USA. A horror movie was even produced by Hollywood that was largely broadcasted via satellites. Many Haitians were able to watch the film and could realize how the Western world was considering one of their most secret traditions. From that time on, any further attempt in collecting new ethnotoxicological information in Haiti was impossible! As a consequence of these two examples, scientists are faced now with considerable difficulties to gather reliable information during new field trips aiming to understand better the complexe pharmacology of these drugs.