• The primary outcome will be the number of patients that achieve an ACR20 response. So we will compare the number of patients that achieved an ACR20 response in the probiotic group to those that achieved an ACR20 response in the placebo group. [ Time Frame: 4 months ] [ Designated as safety issue: No ]
  

• Immunological parameters (TNFα, IL-12, IL-10 and G-CSF) along with the eight components of the ACR20 response will be the secondary outcomes. Serum creatinine and liver function will be evaluated as parameters of any side effects of the probiotics. [ Time Frame: 4 months ] [ Designated as safety issue: Yes ]
  

Patients between 18 - 80 years old who have Rheumatoid arthritis with at least 4 swollen and tender joints will be randomized to receive by mouth two capsules containing placebo or probiotic, Lactobacillus rhamnosus GR-1 and L. reuteri RC-14, daily. The subjects will continue to take the placebo or probiotic, in addition to their RA medications (i.e. ongoing medication and/or other therapy, such as physiotherapy are permitted, except immunotherapy) for three months. At day 0 (visit #1) (when recruited and just prior to starting to take capsules), at day 45 (visit #2), and at day 90 (visit #3), blood samples of approximately 40 ml of blood (8 teaspoons) will be collected by clinical technicians working in the Lab Test Centre at St. Joseph's Health Center. The blood samples will be used to evaluate Erythrocyte Sedimentation Rate (ESR) and C-reactive protein level. In addition, immunological markers like TNFα, IL-12, IL-10 and G-CSF will also be measured. Serum creatinine and liver function will be evaluated as parameters of any side effects of the probiotics.

Probiotics/placebo will be dispensed from the pharmacy and provided to the subjects by the study investigator at the first visit (for the first 45 days) and second visit (for the final 45 days).

At day 0, 45 and 90 (visits 1, 2 and 3) a physical exam will be completed, where the physician will count the number of swollen and tender joints and complete the Physician Global Assessment of Disease activity. In addition, at these times, the patients will be asked to complete the following self-administered questionnaires:

• Health Assessment Questionnaire (HAQ);
• Patient's Global Assessment of Disease Activity
• Patient Assessment of Pain and Assessment of Duration of Morning stiffness.

Patients will also be asked about feeling fatigued or sleepy, as these are standard questions that come with the above-mentioned questionnaires. These are simple questionnaires that will take approximately 15 minutes to complete. In visit 2 and 3 the physician will confirm if the participant is taking the study capsule/placebo correctly, review any new medications the patient has taken since the last visit and will ask about adverse events that may have occurred.

At day 90, subjects will stop taking capsules.

A follow-up phone call will take place 30 days after the completion of the study medication (day 120). If a patient is withdrawn or withdraws from the study prematurely, he/she will be asked to receive a follow-up telephone call 30 days from the date they last took the study product. During the phone call, which should not take more than 10 minutes, the participant will be asked about any medications taken in the past month and about any possible side effects (unwanted effects or health problems) that they may have experienced.