For a 4-month-old with constipation, the safest first option is a small amount of prune, pear, or apple juice, typically 1 to 2 ounces mixed with equal parts water. If that doesn’t help, infant glycerin suppositories can provide quick relief and are considered safe for babies under 2. Beyond those two interventions, most remedies depend on whether your baby is breastfed or formula-fed, and whether they’ve started solid foods yet.
How to Tell If Your Baby Is Actually Constipated
Before trying any remedy, it helps to know what constipation actually looks like at this age, because infrequent pooping alone doesn’t mean there’s a problem. Some breastfed babies go a week or more between bowel movements and are perfectly fine. What matters is the consistency of the stool and how your baby acts while passing it.
Signs of true constipation include hard, dry, pellet-like stools, visible straining or discomfort during bowel movements, a bloated or firm belly, unusual fussiness, and spitting up more than normal. You might also notice your baby clenching their buttocks or arching their body. If the stool is soft and your baby doesn’t seem bothered, they’re probably not constipated, even if it’s been several days.
Breastfed vs. Formula-Fed: Why It Matters
Breastfed babies tend to poop more frequently in the first two months (around 5 times a day compared to about 2 for formula-fed babies), and their stools are generally more liquid. Interestingly, though, breastfed babies are actually 3.5 times more likely to have occasional stretches of infrequent stools. This is usually normal and doesn’t require treatment as long as the stool is soft when it does come.
Formula-fed babies are more prone to genuine constipation because formula is harder to digest and produces firmer stools. If your formula-fed baby is consistently straining and passing hard stools, switching to a different formula may help. Some formulas are designed to produce softer stools. Talk to your pediatrician before switching, since they can recommend a specific type based on your baby’s needs.
Fruit Juice in Small Amounts
The AAP generally recommends avoiding fruit juice before age 1, but they make a specific exception for constipation. Prune, pear, and apple juices contain sorbitol, a natural sugar alcohol that draws water into the intestines and softens stool. For a 4-month-old, offer 1 to 2 ounces of 100% fruit juice (no added sugar) per day. You can dilute it with an equal amount of water to make it gentler on the stomach.
Prune juice tends to be the most effective because it has the highest sorbitol content. Pear juice is a good alternative if your baby doesn’t take to prune juice. Give it once a day and wait 24 hours to see if it helps before offering more. This is a short-term solution, not something to continue daily once bowel movements normalize.
Glycerin Suppositories
If juice doesn’t work or your baby seems very uncomfortable, infant glycerin suppositories are a reliable option. For babies under 2, use half to one pediatric suppository, inserted gently into the rectum. They work by stimulating the bowel and drawing moisture into the stool, usually producing a bowel movement within 15 to 60 minutes. They have essentially no side effects and are available over the counter at any pharmacy.
Suppositories are best used as an occasional rescue tool, not a daily habit. If your baby needs them more than three days in a row, that’s a sign something else is going on and worth a call to your pediatrician.
Gentle Physical Techniques
Simple movements can sometimes get things moving without any products at all. Lay your baby on their back and gently bicycle their legs, pushing each knee toward the belly in an alternating pattern. This mimics the natural motion of the intestines and can help release trapped gas or stool. Gentle clockwise belly massage (following the path of the large intestine) can also stimulate digestion. A warm bath sometimes relaxes the muscles enough to allow a bowel movement.
What to Avoid at 4 Months
Plain water might seem like an obvious fix, but giving water to a baby under 6 months carries a real risk. Their kidneys aren’t mature enough to handle extra water, and even small amounts can dilute the sodium in their blood to dangerous levels. The small amount of water used to dilute juice is fine, but don’t offer plain water as a standalone remedy.
If your baby has started solid foods early (some pediatricians approve starting at 4 months), be aware that rice cereal, bananas, and applesauce are common constipation triggers. Swap these for fruits that loosen stools: peaches, plums, pears, and prunes. If your baby hasn’t started solids yet, don’t introduce them specifically to treat constipation.
Avoid adult laxatives, mineral oil, enemas, or any over-the-counter stool softener unless your pediatrician specifically prescribes it. Some doctors do prescribe polyethylene glycol powder (the active ingredient in MiraLAX) for infants as young as 1 month, but the dosing is very precise and needs medical guidance.
When Constipation Needs Medical Attention
Most infant constipation resolves with the simple measures above, but certain signs point to something that needs a doctor’s evaluation. Blood in the stool, vomiting paired with a swollen belly, failure to gain weight, or constipation that doesn’t respond to any home treatment all warrant a call. Babies under 6 months with persistent constipation are also flagged for closer evaluation, since ongoing issues at this age occasionally signal an underlying condition that needs to be ruled out.