If i have consistent diarrhea that is very foul smelling. .should i be concerned?

Yes: You may have a gastroenteritis type infection. Please call your doctor for an appointment to be seen. This will get you better quicker. In the meantime drink fluids (water, noncaffeinated drinks) to avoid dehydration. Popsicles are also helpful.

Smell doesn't matter: Stool always smells bad. Sometimes worse, but really doesn't matter. However diarrhea lasting longer than a week is usually cause to see a doctor.

If chronic- yes: Chronic diarrhea with a foul smell suggests malabsorption issue or a chronic amoebic infection. If not addressed, you could begin to lose weight, become malnourished, and develop certain signs/symptoms of vitamin deficiency especially Vitamins A, D, E, and K. See your doctor- depending on the details of your case, additional testing can be done together one the exact diagnosis and get treated.