This randomized controlled trial will compare Bacillus clausii (Enterogermina) and a multistrain probiotic preparation (Ecotec) in children aged 1-5 years with acute watery diarrhea. Participants will receive one of the probiotic treatments along with standard therapy including oral rehydration solution and zinc supplementation. The study will evaluate the duration of diarrhea, stool frequency, and stool consistency.

Acute watery diarrhea is a major cause of morbidity among children worldwide, particularly in developing countries. Although oral rehydration solution (ORS) and zinc supplementation remain the cornerstone of treatment, probiotics are increasingly used as adjunctive therapy to reduce the duration and severity of illness.

Bacillus clausii and multistrain probiotic preparations have both demonstrated beneficial effects in children with acute diarrhea. However, evidence comparing their relative effectiveness is limited. This study aims to compare the effectiveness of Bacillus clausii (Enterogermina) and a multistrain probiotic preparation (Ecotec) containing Lactobacillus acidophilus, Lactobacillus bulgaricus, Bifidobacterium species, and Streptococcus thermophilus in the management of acute watery diarrhea in children.

This study is a randomized, open-label, parallel-group controlled trial conducted in the Department of Pediatric Medicine at The Children's Hospital and Institute of Child Health, Lahore. A total of 138 children aged 1-5 years with acute watery diarrhea will be enrolled and randomized in a 1:1 ratio into two treatment groups.

Participants in Group A will receive Bacillus clausii (Enterogermina) once daily for 5 days in addition to ORS and zinc supplementation. Participants in Group B will receive the multistrain probiotic preparation (Ecotec) once daily for 5 days in addition to ORS and zinc supplementation.

The primary outcome is duration of diarrhea. Secondary outcomes include stool frequency and stool consistency during the treatment period. The findings of this study may help identify the more effective probiotic strategy for the management of acute watery diarrhea in children and contribute to evidence-based pediatric practice.

Inclusion Criteria:

1. Patient with Acute watery diarrhea aged 1 year to 5 years.
2. Both genders will be included.
3. Patients whose guardians/ parents will give informed consent will participate in the study.
4. Patients having mild to moderate dehydration will be included in study.
5. Patients having mild to moderate malnutrition will be included in study.

Exclusion Criteria:

1. Children having history of chronic diarrhea.
2. Children having history of blood in stools.
3. Children having cholera.
4. Children with evidence of concurrent systemic infections other than acute diarrhea (e.g. respiratory tract infections, urinary tract infections, measles, meningitis etc).
5. Children with known immunodeficiency disorders or undergoing immunosuppressive treatments (e.g., chemotherapy, corticosteroids).
6. Children who have received antibiotics or zinc within the past 72 hours prior to enrollment, as this may interfere with gut flora and probiotic efficacy.
7. Children who have received probiotics as a treatment for the current episode of diarrhea prior to study enrollment.
8. Children with known allergies or hypersensitivity to probiotic components used in the study.
9. Children who needed I/V antibiotics or I/V rehydration after enrollment.