What treatments should you use for your 4-year-old son who has had diarrhea for 6 days without other symptoms like dehydration or fever and should you worry?

SIX days of diarrhea for any child, espedially a 4-year old, should be checked out by a doctor IMMEDIATELY. The child could suffer severe dehydration and that is NOT GOOD. Ask your doctor for an appointment RIGHT AWAY, and ask if you should give your child fluid such as "Pedialyte" to replenish vital fluids and also ask if you should give him anti-diarrhea medicine in the mean time. He needs to be seen by a doctor RIGHT AWAY. I agree with all the things above. After TWO days take him to the doctor. Get a sterile pot, or boil one out yourself and take a sample with you for testing.