To evaluate the efficacy of 'the perioperative dialogue (PD)' by analyzing salivary cortisol, in 5- to 11-year-old children undergoing day surgery. To deal with anxiety prior to investigations and/or procedures, children need to be confident and informed about what is going to happen. Therefore, intervention strategies should be initiated before admission to hospital. Children (n = 93), 79 boys and 14 girls, scheduled for elective day surgery requiring general anesthesia were randomly recruited into three groups: (i) standard perioperative care (n = 31), (ii) standard perioperative care including preoperative information (n = 31), and (iii) the PD (n = 31). Saliva was sampled for cortisol analysis at specific time points during the pre- and perioperative procedures. The children who received the PD had significantly lower (P = 0.003) salivary cortisol concentrations postoperatively. Moreover, it continuously decreased during the day of surgery compared with the other two groups (P < 0.01). Among the children who received analgesics, the PD group received significantly less morphine (P = 0.014) related to bodyweight: the mean dose was 0.1 mg·kg(-1) (n = 9) in the control group vs 0.04 mg·kg(-1) (n = 6) in the PD group. Irrespective of group, there was a positive correlation between the children's morphine consumption and salivary cortisol concentration (r = 0.56; P = 0.038). The W-B scale score was higher in the group that received morphine (median = 3 vs median=1; P = 0.001). The PD's caring, continuity, and on-going dialogues were associated with low concentrations of salivary cortisol postoperatively and reduced morphine consumption and thus appears to be a valuable complement to standard perioperative care in children undergoing day surgery.