The regulatory specifications for gum arabic (Acacia senegal) are superficial and inadequate to ensure that it is not adulterated with non-permitted gums from other botanical sources. Moreover, the existing specifications do not give the consumer the essential assurance, fundamental to food safety evaluation principles, that the nature and quality of gum arabic used in foodstuffs always conforms to that of the Test Article selected for the toxicological studies which justified the current status ('ADI not specified') of gum arabic as a permitted food additive. The availability of well-preserved gum arabic samples, collected between 1904 and 1939, has enabled invaluable data to be added to those derived from samples from the most recent crops. The resulting analytical data substantiate and greatly extend the quantitative information available previously for the chemical characterization of gum arabic for regulatory and trade purposes. The data confirm that good-quality commercial gum arabic was used previously as the Test Article. There is no evidence that the specific rotation of gum arabic has become significantly less negative in recent years.