RT Journal Article SR Electronic T1 Randomised controlled trials in single patients JF Drug and Therapeutics Bulletin JO Drug Ther Bull FD BMJ Publishing Group Ltd SP 40 OP 40 DO 10.1136/dtb.1998.36540 VO 36 IS 5 YR 1998 UL http://dtb.bmj.com/content/36/5/40.abstract AB Results of large randomised controlled trials may not help in deciding treatment for an individual patient. This may be because the patient differs clinically from those in the trials, or because wide variations between individuals in a trial limit the applicability of results to an individual patient. In these circumstances, a randomised controlled trial in the individual patient (an n-of-1 trial) may help . This approach may also help when the prescriber or patient doubts whether the treatment is, or will be, beneficial,1 when the optimal dosage is uncertain, or to assess whether an unwanted effect is due to a particular treatment.2 Here we discuss the use of this technique.