Asthma is an increasing global health problem that remains uncontrolled in many patients. In this issue, Barnes discusses the pros and cons of new therapeutic approaches for asthma. With the emergence of new variant Creutzfeld–Jacob disease in the United Kingdom and around the world, transmissible spongiform encephalopathies are at the forefront of research, and there is an urgent need for effective drugs to halt the progression of these and other prion diseases. Cashman and Caughey discuss some encouraging developments in treatments for prion disease that have emerged from immunological and chemotherapeutic approaches. A global health problem of another type — the need for new methods of contraception — is discussed in a Science and Society article by Nass and Strauss, in which they outline some strategies to overcome long-standing obstacles to the development of new contraceptives. Further lessons for overcoming some of the barriers to the development of new drugs are outlined in this issue's 'Guide to drug discovery' article: Lombardino and Lowe describe the changing role of the medicinal chemist in the drug discovery process and use this historical perspective to suggest improvements to the current model. Recent successes in medicinal chemistry, along with a better understanding of the genetics, molecular biology and pathophysiology of kinins, pave the way for the application of modulators of kinin receptors as potential therapeutics, as described by Marceau and Regoli. Complex glycans represent another source for new therapeutic agents that have previously not been well exploited. Sasisekharan and colleagues unravel some of the complexities of glycans and reveal the promise that glycans hold for the development of treatments for a range of diseases.