Depends on baby's age and colour la! Formula-fed babies usually punya najis yang lebih padat dan darker compared to breastfed babies, bisa jadi greenish, brownish, or tan colour, semua normal. A few of my mum friends dengan formula babies, their pediatrician said as long as baby is gaining weight, happy, and pooing regularly, takde perlu worry. Tapi if you notice ada blood, very loose/watery consistently, atau baby seems uncomfortable, better check with the doc just to be safe, pediatrician can look at it properly and give you peace of mind!