Intradermal water blocks consist of 4 intradermal injections of 0.05- to 0.1-mL sterile water (using a 1-mL syringe with a 25-gauge needle) to form 4 small blebs, 1 over each posterior superior ...

J Midwifery Womens Health. 2008;53(2):115-122. The mechanisms of action for sterile water injections are not fully clear, but the Gate Control Theory is one logical explanation. This theory was ...