Background: Supplementary dietary fiber and probiotics may improve bowel symptoms due to changes in microbiome and fermentation. The aim of the study was the evaluation of symbiotic with psyllium, ColonFit, in patients with functional colonic diseases. Patients and Methods: A prospective observational study in patients with irritable bowel syndrome, functional constipation and functional diarrhea for a 4-week intake of ColonFit 10 g daily. The type and severity of bowel symptoms (scale 1–5), number and consistency of stool and quality of life features were analyzed in subgroups according to dominant initial symptoms. Results: Complete data were available from 110 patients (mean age 49.9 ± 15.3 years, 58.2% females). Constipation related symptoms were predominant in 46 (41.8%) patients, diarrhea in 28 (25.5%) and mixed type in the rest. The symptoms in constipation predominant group were more severe than in others. The significant change in softening of stool consistency (from 1.9 to 3.8 in Bristol stool scale; p < 0.001), an increase in spontaneous bowel movements (from 3.1 to 5.6× weekly; p = 0,001) and reduction of incomplete bowel movements of 40% and abdominal pain of 42% were observed in constipated patients. The reduction in a number of bowel movement per week (from 17.8 to 13.6; p = 0.001) and improvement of abdominal cramps by 27% and reduction of dietary limitations by 30% were recorded in diarrhea subgroup. The beneficial effect lasted for a two-week follow up after the discontinuation of ColonFit use. Conclusion: The ColonFit use was most beneficial in constipated patients. The improvement of several symptoms was observed in other subtypes of irritable bowel syndrome without any worsening of troubles. The use of the combination of psyllium, inulin and probiotics may offer an effective alternative for the management of functional bowel diseases.