Passive or active drainage can be used after abdominal surgery. Drains aim at eradicating infected or inflammatory tissue fluids and to alarm of undesired events such as bile, pancreatic, or bowel leak. Drains may, however, occlude or be situated away from the postoperative dilemma. Furthermore, drains themselves are susceptible to cause or maintain infection by retrograde contamination, may irritate the peritoneum causing excess ascites formation, and cause pain. Recent scientific evidence suggests that drains are unnecessary after most abdominal operations. Thus, drains should be used only in certain specific operation types such as pancreatic and emergency surgery. In other operations drains can be omitted if no clear risk factors are present.