The prevention of traveller's diarrhea makes use of the selection of foods and drinks, the purification of water, the use of pharmacological substances such as bismuth salicylate and rifaximin (which can only be taken for short periods). The very attractive prospect of preventing travellers' diarrhea without systemic antibiotics has fueled interest in probiotics for this purpose. However, not all probiotics are identical, and the results of studies conducted with a particular agent cannot be generalized to indicate that any probiotic agent would be successful in the same clinical situation. Probiotics such as Lactobacillus GG have been shown to reduce the incidence of diarrhea in travelers in randomized controlled trials. In contrast, another Lactobacillus preparation, non-viable Lactobacillus acidophilus, showed no benefit over placebo in a randomized, double-blind, controlled trial of 174 travelers. The reasons for this are unclear, but could be related to the fact that the bacteria were not viable or a peculiarity of the strain selected for testing.

Inclusion Criteria:

• Healthy bikers
• Able to pass the Amazonia forest by bike

Exclusion Criteria:

• None predifinied