Bariatric Surgery: Possible Risks and Complications

Deciding on bariatric surgery can be difficult. This is major surgery. If you qualify for bariatric surgery, you need to think about the possible risks and complications of having this surgery. Compare these with the risks and complications of not having the surgery. Make sure you know what to expect after surgery, too. You need to be willing to change your lifestyle for the rest of your life. And your body may change greatly in the years after surgery.

Possible risks and complications

As with any surgery, bariatric surgery has certain risks. The risks and complications will vary according to the type of bariatric surgery you have. Make sure you discuss your risks for surgery with your surgeon. These can include:

  • Infection, including in the stomach, the incisions, in the urinary tract or the lungs, as well as other locations 

  • Leaks, blockage at a site where tissue is sewn or stapled together (anastomosis), or bleeding. This will need more procedures or even another major operation to repair.

  • Breathing problems, such as pneumonia, which may need ventilation

  • Acid reflux, ulcers, and/or esophagitis 

  • Dumping syndrome-diarrhea, cramps and other GI symptoms

  • Kidney failure

  • Depressed mood or other psychological issues 

  • Blood clot(s) in the legs that may travel to the lungs or heart

  • Injury to the spleen, sometimes needing removal of the spleen 

  • Recurrent vomiting that needs a procedure to stop the problem

  • Development of a hernia at one of the incision sites (including internally) 

  • Problems from anesthesia

  • Other rare but severe complications 

  • Death

Ongoing concerns after surgery

You still may be concerned about the following after surgery: 

  • After surgery, your body may not absorb all the nutrients it needs, making malnutrition, anemia, or vitamin and mineral deficiency more likely. Vitamin and mineral supplements are needed to prevent this.

  • Dehydration is more likely after surgery. You must take care to drink enough liquids each day.

  • Gallstones may happen and may need more surgery. 

  • You may also experience failure to meet your weight loss goals, or have a weight gain after initial weight loss. 

  • Temporary hair loss is a common side effect of this surgery.

  • Loose folds of skin are common when a large amount of weight is lost. Extra skin can be surgically removed when your weight has stabilized, but this may not be fully covered by your insurance. 


  • American Society for Metabolic and Bariatric Surgery

  • National Heart, Lung, and Blood Institute Obesity Education Initiative