A feeding tube is a medical device used to provide nutrition to people who cannot obtain nutrition by mouth, are unable to swallow safely, or need nutritional supplementation. The state of being fed by a feeding tube is called enteral feeding or tube feeding. Placement may be temporary for the treatment of acute conditions or lifelong in the case of chronic disabilities. A variety of feeding tubes are used in medical practice. They are usually made of polyurethane or silicone. The outer diameter of a feeding tube is measured in French units (each French unit equals 1⁄3 mm). They are classified by the site of insertion and intended use.

There are dozens of conditions that may require tube feeding (enteral nutrition) to prevent or treat malnutrition. Conditions that necessitate feeding tubes include prematurity, failure to thrive (or malnutrition), neurologic and neuromuscular disorders, inability to swallow, anatomical and post-surgical malformations of the mouth and esophagus, cancer, Sanfilippo syndrome, and digestive disorders.

Feeding tubes are used widely in children with excellent success for a wide variety of conditions. Some children use them temporarily until they are able to eat on their own, while other children require them for a longer time. Some children only use feeding tubes to supplement their oral diet, while others rely on them exclusively.

Tube feedings are not recommended for those with advanced dementia. People with advanced dementia who get feeding assistance rather than feeding tubes have better outcomes. Feeding tubes do not increase life expectancy for such people, or protect them from aspiration pneumonia. Feeding tubes can also increase the risk of pressure ulcers, require pharmacological or physical restraints, and lead to distress.

Feeding tubes are often used in the intensive care unit (ICU) to provide nutrition to people who are critically ill while their medical conditions are addressed. Those who are critically ill have decreased nutrient intake, reduced nutrient utilization and increased inflammation and metabolic needs. Malnutrition in critically ill people is associated with death, prolonged hospitalizations, and hospital readmissions. In critically ill people who have malnutrition or at risk of the disorder, individualized medical nutrition therapy (MNT) with a dietician is the preferred initial treatment. MNT involves a nutritional assessment, patient counselling to increase nutritional intake, oral nutritional supplements and if required; tube feeds or total parenteral nutrition (TPN). In critically ill patients, MNT (including tube feedings if needed) was associated with a lower risk of death, with a 27% lower risk of death up to 6 months after hospital discharge, lower risk of hospital readmission, increased weight, and increased protein and caloric intake. Tube feeding is preferred over TPN. High protein tube feedings in the ICU have found no benefits as compared to standard feeding, and in some cases was associated with harm. Early tube feeding (within 24 hours of hospital admission) may also not be beneficial.

As of 2016, there was no consensus as to whether nasogastric or gastric tubes led to better outcomes.

Studies assessing tube feedings outside of the critical care setting are lacking.

There is at least moderate evidence for feeding tubes improving outcomes for chronic malnutrition in people with cancers of the head and neck that obstruct the esophagus and would limit oral intake, people with advanced gastroparesis, and ALS. For long term use, gastric tubes appear to have better outcomes than nasogastric tubes.