Ingredients have been used in industrial manufacture of tobacco products since the early part of the 20th century. However, unlike other consumer goods, until now no regulatory authority has determined how tobacco ingredients should be assessed. Although there is currently no consensus on how added cigarette ingredients should be evaluated, this paper reviews some of the institutional guidance alongside published literature with a view to determining if there is a generally accepted approach in the absence of any strict regulation. Our aim was to review the recommendations, to compare them to the working practices as demonstrated from published studies, and to draw conclusions on currently used methodologies for testing ingredients added to cigarettes. The extent of testing is discussed in the light of practical and theoretical constraints and an example of an industry testing program is presented.