Abstract
The effects of probiotics on human health are positive and well defined in diarrhoea treatment. There are no clinical results regarding the relationship with dose or duration of treatment. The results from clinical studies have not been conclusive in that the effects of probiotic are dependent on strains, acute or chronic gastrointestinal infection and immunological or inflammatory disease and different dose and duration of treatment. The concentration of probiotics needed to obtain a clinical effect is often quoted as≥106 cfu/ml in the small bowel and≥108 cfu/g in the colon. The dose for treatment of an acute illness by a particular probiotic agent may be lower or higher, in the order of 10-fold or 100-fold or more in terms of colony forming units (cfu). In acute infectious diarrhoea it seems that higher doses of probiotics given for short courses are more effective than lower doses. In chronic or immunological diseases (allergic, inflammatory and/or immune diseases) the effects depend also on the interaction with gut immune system and duration of treatment. To evaluate the efficacy of probiotics it may be essential to identify specific target groups of individuals with more specific higher susceptibilities to the potential effects of probiotics.