Antibiotics are currently required to treat patients in hospital when they have an infection, but these antibiotics can cause side effects such as diarrhoea and in some patients a serious form of gut infection with an organism called Clostridium difficile. This organism can produce toxins in the gut causing a severe form of diarrhoea associated with a lot of ill health, and in some circumstances can be fatal. Some studies have shown that yogurts' or Probiotics' (special drinks with a defined concentration of useful bacteria) taken by patients can have a beneficial effect in reducing the diarrhoea associated with antibiotics use. The aim of the present study is to find out whether the use of one of these Probiotics in hospitalised patients taking antibiotics will result in less diarrhoea, less Clostridium difficile infection, as well as cost saving. The study will also analyze the effects of probiotics on quality of life and length of hospital stay.

As part of this study, we will look at both microbiological and immunological markers, in addition to analyzing the overall cost implications by analysis of health economics.

Inclusion Criteria:

• Male/female patients, above 55 years of age Patient has given written informed consent/Assent to take part in the study Patients are receiving antibiotics as inpatients Patients prescribed therapy with single or multiple antibiotics (oral or IV) will be included Antibiotic therapy must be indicated for a minimum of 72 hours Patients must be able to take medication orally Inclusion in the study is approved by the admitting consultant and validated by a member of the trial team within 48 hours

Exclusion Criteria:

• Age less than 55 years Pregnancy Patients on PEG feed. Diarrhoea on admission or within the preceding week Severe life-threatening illness

Subjects with allergy or hypersensitivity to any component of the study product (e.g.: allergy or hypersensitivity to milk proteins) Subjects who had any surgery or intervention in the last 4 weeks Subjects enrolled in another clinical study in the last 4 weeks Subjects who are thought not to comply with the clinical study Subjects presenting with a severe evolving or active pathology or infection of the gastrointestinal tract such as inflammatory bowel disease, Crohn's disease or ulcerative colitis, diverticular disease or liver cirrhosis.

Any condition affecting the pancreas including acute and chronic pancreatitis Patients who had a surgical operation in their bowels in the preceding 3 months A medical condition such that the life expectancy of the patient is predicted at less than 3 months by the admitting consultant and validated by a member of the trial team Immune-suppressed patients (e.g. HIV) Steroid use of Prednisolone greater than 10mg a day (or equivalent of Dexamethasone) for over 2 weeks prior to entering the trial Patients on Cytotoxic drugs Post-transplant patients Any clinical condition affecting the pancreas including acute and chronic pancreatitis Patients with prosthetic heart valves or a history of endocarditis. Patients who have taken probiotic drinks containing live organisms or over the counter probiotic preparations in the past seven days (see Appendix 10) Foreign travel in the last 7 days