The presented review concerns the cross-disciplinary approaches to the subject of blue food and blue colourants, the socio-cultural aspects of blue food and beverage consumption, human health effects, environmental impact, and economic aspects. Blue colour in relation to food is not only about improving visual appeal, to which the addition of food colouring is usually limited when the food is coloured in some way that does not encourage eating. It is also the rich and complex sociological side related to food, that is, not only the food itself but also the background, dishware, and light, depending on whether we want to encourage—to increase consumption—or discourage—to, for example, reduce the amount of food eaten for dietary purposes. The negative side of consuming and disposing of synthetic dyes and the health-promoting aspects of natural dyes are also mentioned, with the economic and environmental aspects of sourcing natural dyes being discussed. The food industry uses blue dyes not only for consumption, but also for food quality control, taking advantage of the pH-dependent colour change properties of the compound.