Hi natalia88, did you experience the diarrhea during the colonic or following it? Same question for the cramping?
Do you know what is in the herbal bowel capsules? How often are you taking them?
It's not that unusual to have loose stools during a colonic, especially if you are using bowel supplements in between sessions, and it is very common afterwards for some hours.
Cramping during colonics is most often associated with dry, hard or impacted stool which is very common in clients suffering from constipation problems, especially during their first few sessions.