The analysis and bioanalysis of natural products presents particular challenges. In some cases, the product found in nature can be decomposed during the isolative process and this may impact upon the choice of the best analytical procedure that is subsequently adopted. In principle a bioassay can be more sensitive but it may not discriminate between different compounds which may be structurally diverse but may have a similar bioactivity profile. Bioassays can take on different forms depending upon the objective of the investigator and can be linked to analytical methods in order to probe levels of efficacy and structure/activity relationships. The development of adjacent technologies (for example, spectroscopy) has facilitated the development of tools to increase the power of analysis and the measurement of structure/function relationships and authenticity/adulteration. Processing is an important aspect of food systems and can give rise to the formation of process-specific components and examples of these are available.