Prospective controlled clinical trials provide the highest level of evidence in palliative care. Both parallel and crossover studies have unique advantages and disadvantages. Excellent knowledge of the patient population, interventions and endpoints are useful in choosing the most appropriate trial. Open pilot studies can assist the investigator in understanding the intervention and measurement tools better before embarking in costly and lengthy controlled trials. More controlled clinical trails are need to generate the evidence that will advance patient management in palliative care.