The investigators examined whether a written plus verbal preoperative counseling for patients undergoing open cholecystectomy would improve perioperative symptoms such as nausea, vomiting and pain.

This was a randomized, single-blinded, clinical study carried out at the Julio Muller University Hospital (Mato Grosso State, Brazil). This study was conducted according to the guidelines laid down in the Declaration of Helsinki and all procedures involving human subjects/patients were approved by the hospital Research Ethics Committee registered under number 697/CEP-HUJM/09. Written informed consent was obtained from all patients.

Except for the preoperative counseling which was received only by the intervention group, all patients received the same protocol of perioperative care.

The main endpoint of the study was the presence and the intensity of postoperative symptoms such as nausea, vomiting and pain. A questionnaire containing a visual analogue scale (VAS) was applied 24h after the operation to measure the intensity of postoperative pain, nausea and the well-being. The VAS consisted of a horizontal line, 100 mm in length, anchored by word descriptors at each end to represent the lowest and the highest intensity of all the symptoms analyzed. The patient was asked to mark in the straight line the point that most likely represents the symptom at the moment. The VAS score of each individual was determined by measuring in millimeters from the left end of the line to the point marked. The questions were: "how severe was your pain during this period of 24h after the operation?", "how severe was the intensity of your nausea during this period of 24h after the operation? ", and "how great is your well-being at the present moment". For the first two questions the words at each end of the line were "no pain" and "severe pain", and "no nausea" and "severe nausea". For the well-being question the words were "no well-being" and "greatest well-being". The Vomiting was also recorded as a categorical variable (yes or no). The length of stay and postoperative complications were also collected.

Inclusion Criteria:

• adult age (18-65 years-old),
• both sexes and
• candidates for an elective open cholecystectomy

Exclusion Criteria:

• having diabetes mellitus,
• chronic kidney failure,
• chronic liver disease,
• serum bilirubin > 2 mg/dL,
• body mass index (BMI) > 35 kg/m2,
• American Anesthesiologists Association (ASA) score > 3,
• gastro-esophageal reflux,
• gastroparesis or intestinal obstruction.

Patients with any non-compliance with the study protocol, who had the choledochus opened or associated operations, who experienced severe intraoperative complications (any type of shock, cardiac arrest or coagulations problems) or experienced prolonged (> 4 h) operative time were also excluded.