Primary nocturnal enuresis is one of the most frequent complaints in paediatric and urologic practice. Physicians face the dilemma of whether or not to treat primary nocturnal enuresis since the trend towards spontaneous remission is countered by social disadvantages and reduced self esteem of the children affected and their families. We reviewed randomised, controlled trials investigating efficacy and adverse effects of current medical treatment for primary nocturnal enuresis. Only desmopressin and imipramine displayed significant effects in reducing wet nights: when compared with baseline bedwetting or placebo controls, 30-70% of the studied children achieved therapeutic success. For drugs such as indometacin or oxybutynin, convincing studies displaying a significant positive effect are still needed. However, considering the adverse effects profiles of desmopressin and imipramine it can be seen that imipramine is associated with about twice as many unwanted reactions. More importantly, a serious adverse effect of imipramine is sudden cardiac arrest. In general, adverse effects with desmopressin are rare and mild, but there have been a number of case reports of hyponatraemic hypervolaemia associated with coma and seizures. Of these, many cases were attributed to excess water intake before taking the drug and all children recovered fully. In summary, if medical treatment is considered, preference should be given to desmopressin.