There are various reasons for children’s dark lips, including heart diseases, such as congenital heart disease, heart valve disease, serious lung infections, asthma, renal insufficiency and other diseases can cause the occurrence of dark lips, but of course, some children are born with dark lips or use certain foods with natural pigments. Parents need to carefully observe the symptoms and changes of their children to see if there are any other abnormalities besides the dark lips, and then go to the hospital in time.