This is a double blind, randomized, placebo-controlled study. One-hundred subjects are randomized to receive either YOVIS or placebo over a period of 10 days.

The purpose is to determinate the efficacy of the treatment in subjects treated with antibiotic therapy, by measuring occurrence of Antibiotic Associated Diarrhoea (AAD) from baseline to the end of the observation period (28±2 days)

AAD is defined as clinically unexplained diarrhea that occurs in connection with antibiotic administration. Any antibiotic could potentially cause AAD, but broad-spectrum antibiotics that predominantly target anaerobes and are poorly absorbed, such as clindamycin, cephalosporins (cefixime and ceftriaxone), and amoxicillin-clavulanate, have a higher AAD incidence (Turck D, 2003). It has been reported that the highest rates of AAD in 650 pediatric cases were associated with amoxicillin/clavulanate (23%), penicillin A or M (11%) and erythromycin (16%).

In the present trial, adult population already under antibiotic therapy with ampicillin/amoxicillin, cephalosporins and clindamycin, will be selected, in order to capture the highest possible diarrhea events, with a limited number of subjects.

YOVIS, the Investigational Food Supplement (IFS), is an oral formulation (capsules) containing definite mix of live probiotics already marketed by Alfa-Sigma as food supplement since September 2017.

Placebo is an oral formulation of inert capsules. Placebo and YOVIS are identical in shape, size, colour and taste.

One-hundred (100) subjects will be randomized to receive either YOVIS or placebo (1:1) over a period of 10 days.

In case all inclusion/exclusion criteria are met, the subject will be randomized at the baseline visit to one of two masked trial treatments. Further phone contacts are scheduled on day 10±2 and day 21±2, a final visit at site is scheduled on day 28±2.

The primary objective of this study is to assess, versus placebo, the efficacy of a 10 days treatment with YOVIS in preventing the incidence of AAD in subjects under antibiotic therapy.

Inclusion Criteria:

1. Written informed consent, personally signed and dated by the subject.
2. Subjects of both sexes between 18 and 65 years of age (limits included), with no limitation of race.
3. Patients being prescribed or having started an antibiotic therapy with ampicillin/amoxicillin, cephalosporins and clindamycin in the 48h preceding the screening.
4. Antibiotic therapy prescription with a lasting of at least 3 days but no more than 14 days.
5. Subject able to comprehend the full nature and purpose of the study, available to cooperate with the Investigator and to comply with the requirements of the entire study.

Exclusion Criteria:

Inclusion criteria Subjects will be included in the study if they meet all the following criteria.

1. Written informed consent, personally signed and dated by the subject.
2. Subjects of both sexes between 18 and 65 years of age (limits included), with no limitation of race.
3. Patients being prescribed or having started an antibiotic therapy with ampicillin/amoxicillin, cephalosporins and clindamycin in the 48h preceding the screening.
4. Antibiotic therapy prescription with a lasting of at least 3 days but no more than 14 days.
5. Subject able to comprehend the full nature and purpose of the study, available to cooperate with the Investigator and to comply with the requirements of the entire study.

Exclusion Criteria

Subjects will be excluded if they meet any of the following criteria:

1. Pregnant or breast-feeding woman.
2. Known hypersensitivity or allergy to the active ingredients and/or to any component of the probiotic mix.
3. Subject with known food intolerance (eg. milk protein, gluten..)
4. Subject who has taken during the 2 weeks prior to inclusion, who is currently taking or plans to take other orally administered food supplements except the study product
5. Use of antidiarrhoeic drug is forbidden (maintenance of stable and regular treatment started more than 2 weeks before screening visit is allowed)
6. Active diarrhea at the time of the screening visit
7. Non controlled intestinal disease
8. Any antibiotic therapy in the 30 days preceding enrolment
9. Active participation in another clinical study
10. Subject with one or more psychiatric disturbances, such as: alcoholism, substance abuse or dependency disorder, bipolar disorder, schizophrenia, or other personality disorder.

YOVIS, the Investigational Food Supplement (IFS), is an oral formulation (capsules) containing definite mix of live probiotics. Placebo is an oral formulation of inert capsules. Placebo and YOVIS are identical in shape, size, colour and taste. Product test and placebo capsules will be indistinguishable.

Investigational food supplement products will be packed in an individual way for each subject included in the investigation.