['The purpose of this study is to determine whether chiropractic manipulation is associated with any measurable changes in the difference between the arterial blood pressures on the left and right before and after treatment in normotensive subjects.', 'A nonrandomized, matched pair, controlled clinical trial, with the treatment (manipulation) group and control (resting) group matched for age and sex, was performed in chiropractic student clinics in London, UK. The treatment group consisted of 35 new patients presenting to a single student chiropractor between the start of April 2003 and the end of August 2003. The control group consisted of 35 nonpatients matched for sex and age. The intervention was chiropractic manipulation. Preintervention and postintervention systolic and diastolic blood pressures were recorded in both arms through the use of a digital oscillometric sphygmomanometer.', "A significant difference was found between the pre- and posttreatment blood pressure differences for systolic pressures (P = .01), but no significant difference was found in either set of control data or the treatment diastolic values. A significant difference was also found between the treatment and control group's preintervention systolic differences (P = .002), but not between the groups at any other time."] Does chiropractic manipulation affect the difference between arterial systolic blood pressures on the left and right in normotensive subjects?