Green Baby Poo: What Your Baby’s Nappy is Really Saying?

If you're a parent, chances are you've experienced 'the green poo panic'. You open the nappy, expecting the usual, and are met with a startling shade of emerald, chartreuse, or even a deep forest green. Your mind races: "Why is my baby’s poo green?". Thankfully, you are not alone, it's one of the most common reasons parents worry about their baby's bowel movements¹.

The good news? More often than not, green baby poo is completely normal and no cause for alarm. Phew! But wouldn't it be great to have a little expert in your pocket, ready to decode those colourful surprises?

Now you can. With the Aptaclub AI Poo Checker, you can get instant analysis of your baby’s stool from a simple photo. So, if you've got questions you can just Poogle It!

Let’s unpack the mystery of green baby poo and give you the lowdown on what’s usually behind that verdant hue.

Before we jump into the green, let's remember that baby stool colours can be quite a spectrum. What’s considered normal baby poop can vary significantly depending on age and feeding method². Green, surprisingly, fits into that normal range more often than you might think.

Remember those first few days after your newborn arrived? A newborn’s first stool, meconium, is often a thick, tar-like black or very dark green³. This is entirely expected and healthy. Following that, they move into the transitional stool phase, which is typically brownish-green. This early green is just their digestive system getting started and clearing out what was in their tiny bodies before birth. So, if you see green in those first few days, consider it a perfectly normal "Welcome to the World!" message.

Beyond the newborn phase, green baby poo can still make an appearance and often it's nothing to worry about. Here are some common, and usually harmless, culprits:

If you're breastfeeding, you might occasionally notice your baby's stool is a brighter, frothy green. This is usually when milk moves through their gut more quickly than usual, often because there's a strong milk flow or oversupply⁷. Previously, it was thought that green stools were caused by babies getting too much foremilk and not enough hindmilk. However, we now know that fat content in breastmilk increases gradually during a feed — there’s no clear ‘switch’ between foremilk and hindmilk. In cases of oversupply, babies may take in large volumes of milk quickly, leading to what's sometimes called lactose overload. This can cause faster gut transit, resulting in green, frothy, or even explosive poos. It’s usually nothing to worry about if your baby is otherwise content and gaining weight well — but if you're concerned or your baby seems uncomfortable, a lactation consultant can help you assess feeding patterns and milk flow.

Just like with adults, what your baby eats (or what mum eats, if breastfeeding) can directly influence the colour of their stool.

• Breastfeeding Mum's Diet: If you're breastfeeding and have recently eaten a lot of green, leafy vegetables (like spinach or kale), or foods with green food colouring, traces can pass into your breast milk and show up in your baby's nappy⁴.
• Formula Type: Some infant formulas, particularly those fortified with iron or extensively hydrolysed ones, can lead to a darker green or olive-green poo. This is a common and normal side effect².
• Introducing Solids (Weaning): Once your baby starts weaning and exploring solid foods, their digestive system is getting used to a whole new world. Green vegetables like peas, spinach, or broccoli can certainly turn their poo green. Even certain fruits or new baby cereals can sometimes have this effect. It’s their tiny tummy learning the ropes!

If your baby is taking iron supplements, or certain medications, this can also result in a dark green or almost blackish-green poo. Iron can cause stool to darken, and this is a normal occurrence when supplementing². Always check with your GP or pharmacist if you're concerned about medication side effects.

While many cases of green baby poo are harmless, there are times when it's accompanied by other symptoms that warrant a chat with a healthcare professional. We're here to empower you with information, not alarm you, but it’s always important to know when to seek advice.

If your baby's green poo is accompanied by other signs of illness, it might indicate an infection. Look out for:

• Fever
• Vomiting
• Excessive fussiness or irritability
• Refusal to feed
• Signs of dehydration (e.g., fewer wet nappies, dry mouth, sunken fontanelle)
• Mucus or blood in the poo (more on this in other blogs!)

If you notice these additional symptoms with green poo, it's always best to consult your GP⁵.

Sometimes, persistent green baby poo (especially if it's consistently watery, contains mucus or blood, or is accompanied by other symptoms like a rash, eczema, excessive gas, or severe fussiness) could point towards an infant food sensitivity or allergy. Common culprits include cow's milk protein allergy in formula-fed babies, or something in the breastfeeding mother's diet⁶. If you suspect an allergy, speaking to your GP or paediatric dietitian is crucial for proper diagnosis and guidance.

It’s completely normal to experience a bit of parental anxiety when you see something unexpected in your baby's nappy. The good news is you don't have to navigate these concerns alone. Aptaclub's AI Poo Checker is here to be your trusted partner to help you understand about what your baby’s nappy is trying to tell you.

Our first  AI-powered web tool offers instant analysis of your baby's poo by simply uploading a photo from your phone⁷. Built on a huge database of 3.5 million nappies deployed in over 40 countries and developed by our science experts following 50 years of research in infant health and nutrition, this unique infant stool guide or stool chart is designed to give you clarity^{7, 8}. It helps you identify normal stool colours and consistency, effortlessly record changes over time, and provides answers within seconds. It truly helps to alleviate parental anxiety and support your conversations with healthcare professionals.

So, the next time that green shade appears, don't just stare at it in bewilderment. POOGLE IT!"

^{*The Aptaclub AI Poo Checker is not a diagnostic tool and does not provide medical insights about your baby’s digestive health. It does not replace the advice of a healthcare professional.}