Communication between medical staff and patients about treatment efficacy elicits expectations of benefit and improves treatment outcomes. While demonstrated in multiple studies via different research methodologies, uniform communication protocols have not been adopted in clinical practice. Here, we summarize the results of two sister studies aimed at bridging this gap. Women undergoing C-section (study 1, randomized controlled trial) and patients undergoing general or otolaryngologic surgeries (study 2, control group design) were recruited and assigned to the "regular communication" (RC) or "enhanced communication" (EC) arms. The EC arm received positive information about treatment, while the RC arm received no such information. In both studies, the primary outcome was change in pain intensity; in study 2, an additional outcome was morphine consumption. Eighty women successfully completed study 1, and 102 patients successfully completed study 2. In both studies, significant time*group interactions were observed (p < 0.001). The analgesic effect was virtually twice as large in the EC arm compared to the RC arm. In study 2, in the last two timepoints of assessment, participants in the EC arm also consumed fewer doses of opioids than participants in the RC arm (p < 0.001). No significant differences were found in vital signs. We provide ecological evidence that positive information about treatment significantly decreases pain and opioid consumption during routine clinical care. This study and others could encourage healthcare providers to harness the powerful effects of patients' expectations of benefit to improve analgesics outcomes and, potentially, the outcomes of other symptoms.