Context: The neuraxial blocks, spinal anesthesia and epidural anesthesia are among the most frequently performed procedures worldwide, and despite the advancements of medical equipment, remain dependent on experience and practice of the anesthesiologists. Although antisepsis takes part of the daily routine, there are still no solid scientific evidence of the most appropriate antiseptic for these procedures.

Objective: To compare the 70% alcohol and 0.5% chlorhexidine alcohol solution in skin antisepsis for the neuraxial blocks.

Methods: This is a clinical trial, a prospective, randomized study. There will be selected, consecutively, 70 patients candidates for neuraxial blocks. Patients will be randomly assigned to group A (n = 35), in which the antisepsis will be performed with alcohol 70%, and to group B (n = 35), in which the antiseptic will be performed with the 0.5% chlorhexidine in alcoholic solution. Samples will be collected with swabs in an area of 25 cm² for bacterial cultures three times: in pre-antisepsis moments, in the second minute after antisepsis, and immediately after the puncture. The number of colonies forming units per square centimeter (CFU / cm²) will be counted. The data will be analyzed statistically.

Inclusion Criteria:

• Patients between 18 and 65 years of age , without restriction as to sex, ethnicity, education or social class;
• Patients who are undergoing neuraxial blockade by indicating the anesthesiologist responsible for the procedure

Exclusion Criteria:

• comorbidities or conditions which constitute a contraindication for the neuroaxial block ;
• Body mass index (BMI ) greater than 30 kg / m2;
• Ongoing infection;
• Use of antibiotics in the last seven days;
• Skin lesions at the puncture site ;
• Refusal to participate.