General surgery is a surgical specialty that focuses on alimentary canal and abdominal contents including the esophagus, stomach, small intestine, large intestine, liver, pancreas, gallbladder, appendix and bile ducts, and often the thyroid gland. General surgeons also deal with diseases involving the skin, breast, soft tissue, trauma, peripheral artery disease and hernias and perform endoscopic as such as gastroscopy, colonoscopy and laparoscopic procedures.

General surgeons may sub-specialise into one or more of the following disciplines:

In many parts of the world including North America, Australia and the United Kingdom, the overall responsibility for trauma care falls under the auspices of general surgery. Some general surgeons obtain advanced training in this field (most commonly surgical critical care) and specialty certification surgical critical care. General surgeons must be able to deal initially with almost any surgical emergency. Often, they are the first port of call to critically ill or gravely injured patients, and must perform a variety of procedures to stabilize such patients, such as thoracostomy, cricothyroidotomy, compartment fasciotomies and emergency laparotomy or thoracotomy to stanch bleeding. They are also called upon to staff surgical intensive care units or trauma intensive care units.^{[citation needed]}

All general surgeons are trained in emergency surgery. Bleeding, infections, bowel obstructions and organ perforations are the main problems they deal with. Cholecystectomy, the surgical removal of the gallbladder, is one of the most common surgical procedures done worldwide. This is most often done electively, but the gallbladder can become acutely inflamed and require an emergency operation. Infections and rupture of the appendix and small bowel obstructions are other common emergencies.

This is a relatively new specialty dealing with minimal access techniques using cameras and small instruments inserted through 3- to 15-mm incisions. Robotic surgery is now evolving from this concept (see below). Gallbladders, appendices, and colons can all be removed with this technique. Hernias are also able to be repaired laparoscopically. Bariatric surgery can be performed laparoscopically and there are benefits of doing so to reduce wound complications in obese patients. General surgeons that are trained today are expected to be proficient in laparoscopic procedures.

General surgeons treat a wide variety of major and minor colon and rectal diseases including inflammatory bowel diseases (such as ulcerative colitis or Crohn's disease), diverticulitis, colon and rectal cancer, gastrointestinal bleeding and hemorrhoids.

General surgeons can specialise in Upper Gastro-intestinal (or foregut) surgery, which includes the surgical treatment of diseases of the stomach and oesophagus, liver, pancreas and gallbladder. In the UK, Upper GI surgeons can subspecialise further as benign surgeons, dealing with hiatus hernias and gallbladder diseases, bariatric surgeons, providing surgical care for weight management and metabolic diseases, or oesophago-gastric surgeons, dealing with complex problems related to the upper gastrointestinal tract (the foregut), including cancer. Surgical care of complex liver and pancreatic problems (including liver cancer and pancreatic cancer) is undertaken by Hepatobiliary and Pancreatic Surgery sub-specialists.

General surgeons perform a majority of all non-cosmetic breast surgery from lumpectomy to mastectomy, especially pertaining to the evaluation, diagnosis and treatment of breast cancer.