Yes when a baby is teething or beginning to teeth the diarrhea is one of the signs of teething in babies.
Some other signs and symptoms of teething in babies besides diarrhea are things such as irritability, disrupted sleep, swelling or inflammation of the gums, drooling, loss of appetite, rash around the mouth and also mild temperature.
A few other signs of teething in babies are increased biting and gum-rubbing and even ear-rubbing.
Teething is painful for the baby and the baby will likely cry and fuss until the teething is over.
You can give the baby some teething rings to help ease the teething pain and use some teething pain medicine also to help stop the pain.
Eventually the teething pain will stop and also the babies poop consistency can change and be more acidic which can cause diaper rash.
So make sure to use diaper rash cream on your babies bottom when changing diapers and make sure to change a poop diaper right away to avoid a diaper rash.