My Baby Is 1 Month Old And Is Breastfed. From

My baby is 1 month old and is breastfed. From two three days he is having waterry with curd like stool. When he poops the Curd like substance remained in his underwear and the waterry part drains out. No other symptoms are seen with this. Also the color of the stool remains in the cloths even after washing them. What causes him this kind of stool? Is it a sign to go and see a doctor or it is normal? Please answer.