The May 2009 issue of Drug and Therapeutics Bulletin (DTB) contains an editorial and four articles. The editorial discusses the large number of epilepsy medications available, questions the rationale of developing more and asks whose responsibility it is for undertaking trials that inform clinical decisions. The issue also includes an update on treatments for head lice, a review of the role of ▼colesevelam in cardiovascular prevention, an explanatory article about summary of product characteristics (SPCs), and the third in a series of Understanding Statistical Terms articles, covering topics relating to study design. A podcast outlining what is in the May issue is also available via our website www.dtb.bmj.com.