Abstract: Insects make great use of chemicals in communication, attack and defense. Social insects make still greater use of themin communication. Ants, particularly, make extensive use of communication chemicals, and have received the attentionof chemists in discovery of these substances. These chemicals are produced in, and often stored by exocrine glands.The wide range of chemical compounds in exocrine glands of ants are illustrated here with examples. They extend overa broad spectrum of volatile organic compounds, most of them used in communication, as part of the social organisation of species. Illustrative examples of their chemical abilities are found among trail pheromones, defensive secretions, alkaloidal venoms, antibiotics, alarm pheromones, territorial marking and others. In many, but by no means all,examples, we know the function of these compounds, although we still know very little about how they may act togetherto convey more information. This review is written for a broad audience of entomologists to show the great diversity ofsubstances used by ants. Compounds are grouped by the glands in which they have been found.