Following on from the first article in this series (Vol 12(18): 1091-5), which described the history of diabetes, this article, the second of three literature reviews, explores the early production and development of insulin, from its initial production in a university laboratory to becoming a major pharmaceutical product. Also discussed are the various forms of insulin developed over the last 80 years and their means of delivery to the patient. The future is considered and the development of insulin analogues (substances that mimic the effect of human insulin) is described. The article also looks at the introduction of DAFNE (dose adjustment for normal eating) - an intensive programme of education aimed at teaching individuals the necessary skills to adjust their own insulin injection dosage to reflect their individual eating patterns.