Discussing risks and benefits of treatments or care options is becoming an increasingly important part of modern health care. This paper reviews the literature about manipulations of risk and benefit information in the clinical setting. There is a paucity of evidence in this field, particularly when examining specific manipulations. Only three categories of manipulation had three or more studies. The available evidence shows that the way information is presented can have significant effects on decisions made. The largest effects are evident when relative risk information is presented, as compared with absolute risk data. In addition, "loss framing" is more effective in influencing screening uptake behaviors than "gain framing" (odds ratio 1.18 [95% confidence interval 1.01-1.38]). There is also a pattern of evidence from studies comparing simpler with more complex information, more data with less, and those comparing numerical with verbal descriptions of risks. These studies suggest that providing more information, and which is more understandable to the patient, is associated with improved patient knowledge and a greater wariness to take treatments or participate in trials. These findings can contribute to efforts to improve communication between professionals and patients.