To the Editor.—Astudillo et al1 recently reported that pneumoperitoneum is a valuable adjunct as a preparatory technique prior to repair of ventral hernias. However, the use of air for this procedure should be regarded with unease. Reports of air embolism from the introduction of air into the peritoneum, either diagnostically or surreptitiously, has the potential for a fatal outcome. Carbon dioxide has been used for more recent diagnostic procedures, such as laparoscopy, and embolic accidents with this gas are not likely to cause injury. Perhaps, with the increasing use of induced pneumoperitoneum as an adjunct to repair of ventral hernias, the danger of using air as the inflating gas should stimulate the singular use of a rapidly absorbed and excreted gas such as carbon dioxide.