This paper stresses the importance for the good practice of conservation and restoration of correctly identifying the dyes in museum textiles. Three examples of identification demonstrate the truth implied in the title of this article. The availability of known authentic samples of fibers and dyes is the first requirement for this study, the second being that of selecting appropriate techniques for making a positive identification of each of the dyes. The first identification reported concerns a red dye used in pre-Columbian Peru, the relbunium. Several authentic varieties of this plant were collected so that the resulting color could be compared with that obtained from the hermes insect as standard material. Solution spectrophotometry was the technique used for analysis. The results of this study are discussed. A sample of material from Oaxaca in Mexico was also investigated for the presence of cochineal. Here the kind of metal used as a mordant was found to largely determine the resulting shade. A similar sample analysis was carried out on a Navajo blanket. A third study involves a coronation mantle worn in the 12th century by the Holy Roman Emperors, thought to have been dyed with Palermo purple. The unfortunately destructive analysis of 5cm. of a single yarn proved the dyestuff to have been the kermes insect. The text includes some remarks on the importance of trade in dyestuffs in the world of the early explorers; they were then called drugs and were only second to gold and silver in value.