The human body odour is individually specific and relatively stable due to its genetic bases. However, numerous factors affect its hedonic quality, such as hormonal changes, affective states, diseases, and diet, which is often considered the most significant source of variation. The body odour can be influenced directly by specific aromatic compounds or their metabolites from the diet and indirectly by diet quality and food deprivation. Numerous volatile compounds may emanate in breath odour or, after being metabolized by the digestive system, can affect the axillary odour, odour of urine, faeces, amniotic fluid, breast milk, and mother’s diet even the body odour of her newborn baby. The effect of diet on human body odour quality will be illustrated in several our studies that showed, for example, that red meat consumption negatively affects hedonic valence of body odour, while garlic consumption and restoration of caloric intake after food deprivation has positive effects. Mechanisms of odour changes include direct excretion of specific chemicals or metabolites directly derived from the diet or more complex pathways, especially in the case of skin glands where chemicals from the diet are usually transported via the bloodstream and might be metabolized further in the liver. However, for most substances, mechanisms and metabolic pathways of such changes are not known, and more empirical work in this fascinating area of chemical communication is needed.