This study evaluates the benefits of probiotics in patients with fibromyalgia syndrome.

Probiotics has demonstrated to be effective in the management of anxiety and depression. Although these results are promising, more research is needed to explore the role of probiotics to improve physical, emotional and cognitive processes in different clinical populations that are associated with altered microbiome. Thus, the main aim of the present project is to explore whether the oral intake of probiotics might provide benefits to a group of patients with fibromyalgia.

The investigators expect to found significant differences between some physical, emotional and cognitive measures assessed pre- and post-treatment demonstrating the effects of microbiota on the Central Nervous System as well as its potential as a therapeutic tool for the treatment of Fibromyalgia.

Inclusion Criteria:

• Fibromyalgia syndrome diagnosis.
• No treatment with antibiotic.
• More than a year of diagnosis
• Agreement to participate in the study.

Exclusion Criteria:

• Severe physical disability.
• Malignancy.
• Pregnancy
• Psychiatric illnesses (eg, schizophrenia or substance abuse).
• Medication usage other than as-needed analgesics (excluding long-term narcotics).