A feeding tube delivers liquid nutrition directly into your stomach or small intestine, bypassing the mouth and throat entirely. Formula flows through a thin, flexible tube that’s either threaded through the nose or inserted through a small opening in the abdomen. The tube connects to a bag or syringe of nutrient-rich liquid, and feeding happens by pump, gravity, or manual push, depending on the setup and your daily routine.
Types of Feeding Tubes
Feeding tubes fall into two broad categories: short-term tubes that go through the nose, and long-term tubes that go directly through the skin into the stomach or intestine. The right type depends on how long you’ll need it and where in the digestive tract the formula needs to arrive.
Nasogastric (NG) tubes are the most common short-term option. A thin tube passes through the nose, down the throat, and into the stomach. Nasojejunal (NJ) tubes follow a similar path but extend further, reaching the jejunum (the middle section of the small intestine). These nasal tubes work well for days to weeks but become uncomfortable and can irritate tissue over longer periods.
For feeding that will last months or years, a tube is placed through the abdominal wall instead. A PEG tube (percutaneous endoscopic gastrostomy) enters directly into the stomach through a small incision in the abdomen. A PEJ tube follows a similar approach but delivers formula to the jejunum. There are also combination tubes (PEG-J) that pass through the stomach and extend into the jejunum, useful when the stomach can’t handle formula but the intestine can.
Jejunal tubes are typically chosen for people who have a high risk of formula backing up into the esophagus, or whose stomachs don’t empty properly. Stomach-level tubes are simpler to manage and allow a wider range of feeding schedules.
How a PEG Tube Is Placed
PEG placement is the most common procedure for long-term feeding access. It requires sedation but not general anesthesia, and it’s performed by a two-person team. A doctor passes a thin camera (endoscope) down the throat into the stomach and inflates the stomach with air. From the outside, a second person watches for the light shining through the abdominal wall, which shows exactly where the stomach sits closest to the skin surface.
At that spot, the skin is numbed with a local anesthetic, and a small incision (roughly half an inch wide) is made. A needle passes through this incision into the stomach, followed by a guide wire. The endoscope inside the stomach captures the wire with a small snare, pulls it up through the mouth, and attaches it to the feeding tube. The tube is then drawn back down through the throat and pulled out through the abdominal incision, so one end sits inside the stomach and the other exits through the skin.
A small disc called an internal bumper holds the tube in place inside the stomach, while an external bumper on the outside of the skin keeps it from sliding inward. The external bumper sits about 1 to 2 centimeters from the abdominal wall, leaving just enough room to prevent pressure on the skin. The whole procedure typically takes under 30 minutes.
What’s in the Formula
Tube feeding formula is a complete liquid diet, engineered to deliver every nutrient your body needs: protein, carbohydrates, fat, vitamins, minerals, and water. It looks something like a thin milkshake and comes in sealed containers ready to pour into a feeding bag or syringe.
Formulas vary in caloric density from 1.0 to 2.0 calories per milliliter. A standard formula at 1.0 cal/mL means you’d need about 1,500 to 2,000 mL daily to meet typical calorie needs. Higher-density formulas (1.5 or 2.0 cal/mL) pack more calories into less volume, which helps when fluid intake needs to be limited, such as with kidney or heart conditions. Protein content also varies widely, from about 40 grams per liter in standard formulas up to 94 grams per liter in specialized high-protein versions.
Some formulas are designed for specific conditions. There are versions with modified carbohydrate profiles for people managing blood sugar, high-protein formulas for wound healing, and pre-digested (peptide-based) formulas for people whose intestines have trouble absorbing intact proteins. Your dietitian selects a formula based on your calorie needs, medical conditions, and how well your gut absorbs nutrients.
Three Ways Formula Gets Delivered
There are three methods for getting formula through the tube, and each one fits different needs and lifestyles.
Bolus feeding is the closest to eating a regular meal. You use a large syringe to push a set amount of formula through the tube in one sitting. This happens four to eight times per day, with each session lasting about 15 to 30 minutes. It offers the most freedom between feedings and works best for people whose stomachs tolerate larger volumes at once.
Gravity drip uses a bag hung on a pole above you. Formula flows down through the tubing by gravity alone, controlled by a small roller clamp that adjusts flow speed. It’s simple and doesn’t require electricity, but the flow rate can be inconsistent and needs to be checked frequently.
Pump feeding is the most precise method. An electronic infusion pump threads the formula at a controlled, steady rate, often over many hours. Continuous pump feeding can run overnight while you sleep, freeing up daytime hours. Pumps vary in size and complexity. Some are small enough to fit in a backpack, making it possible to receive nutrition while going about your day.
Flushing the Tube
Water flushes are essential to keeping a feeding tube clear and functional. Formula is sticky, and residue builds up inside the tube over time. Without regular flushing, the tube clogs, and clearing a clog is far more difficult than preventing one.
The standard practice is to flush with about 120 mL (roughly half a cup) of water before and after each feeding. If you take medications through the tube, each medication also needs a flush of 30 to 50 mL before and after. These flushes double as hydration. Since you’re not drinking water by mouth in most cases, the flush water may be your primary fluid source. A typical daily target is around 1,000 mL of additional water through the tube, delivered either through feeding flushes or as separate water boluses spread throughout the day, for example 250 mL every six hours.
Caring for the Tube Site
If you have a tube placed through the abdomen, the skin around the insertion point (called the stoma) needs daily cleaning. For the first one to two weeks, your care team will likely ask you to use sterile technique, meaning sterile saline and sterile gauze. After the site heals, mild soap and water with a cotton swab or clean gauze is usually sufficient. You’ll clean the area one to three times per day, gently removing any crusting or drainage from both the skin and the tube itself.
Ointments, powders, and sprays should stay away from the site unless specifically recommended. These can trap moisture and promote infection rather than prevent it. Signs that something is off include redness, swelling, warmth, or unusual drainage around the tube. Some mild redness in the early healing period is normal, but persistent or worsening irritation needs attention.
Common Problems
The most frequent issue is tube clogging, almost always caused by inadequate flushing or medications that weren’t properly dissolved before being pushed through the tube. Crushed pills that don’t fully dissolve are a common culprit. Using liquid versions of medications when available, and flushing between each separate medication, significantly reduces clog risk.
Formula intolerance, which can include nausea, bloating, cramping, or diarrhea, affects up to 20% of people on tube feeding and as many as 50% of those who are critically ill. Slowing the infusion rate, switching formulas, or adjusting the feeding schedule often resolves these symptoms.
Aspiration, where formula travels backward into the esophagus and enters the lungs, is the most serious risk. Keeping the head of the bed elevated to at least 30 degrees during feeding and for 30 to 60 minutes afterward reduces this risk substantially. For people with repeated aspiration issues, switching from a stomach-level tube to a jejunal tube can help, since formula delivered past the stomach is far less likely to reflux upward.
With PEG tubes specifically, the internal bumper can sometimes migrate, causing a blockage at the stomach’s exit, or it can erode into the stomach wall in a condition called buried bumper syndrome. Both are uncommon but require medical intervention to correct, usually by repositioning or replacing the tube.