A quick question about my 8month old male lab. For the past few days his flatulence has been very bad?

In the last 2 days he has had diarreah. His diet has not changed. he is still on 2 cups a day of royal canin puppy food and the ocional treat. As labs do he eats everything that is in front of him be it food or not. Is this a common problem or should he be taken to the vet? (his appetite has not changed and he stills drinks alot each day, nor have his levels of energy. he stills runs around like a mad man.) Any help would be greatly appreciated.