OBJECTIVES: To demonstrate that the long term use of chondroitin sulfate (CS) for patients suffering osteoarthiritis (OA) induced less co-prescriptions. METHODS: Two groups were compared, patients treated less than 6 consecutive months (short term) with CS and patients treated more than 6 consecutive months (long term) with CS during 2001-2002 on the IMS Disease Analyzer database. The objective was to compare the co-prescriptions related to OA for both groups of patient in the 12 months following the study period. In our analysis, medical consultations for OA and OA prescriptions including CS, NSAIDs, analgesics, coxibs and gastro-protective agents were taken into account. RESULTS: We obtained two groups of respectively 56,525 and 24,732 patients treated with CS for their OA in the short and long term groups. In the follow up period, patients with short term and long term treatment had respectively in term of co-prescriptions 37% vs. 38% of NSAIDs, 75% vs. 71% of analgesics and 21% in both groups of coxibs. But the mean length of treatment's days by co-prescriptions were respectively of 40 vs. 37 for NSAIDs, 82 vs. 68 for analgesics and 79 vs. 59 for coxibs (p<0.01). CONCLUSION: The results of this survey allowed us to conclude that in addition to the fact that the use of CS in OA is more efficient with long term treatment, it was also safer compared to short term treatment. A long term treatment reduces the length of treatment of each co-prescriptions. The saving of 20 days of coxibs treatments, 3 days of NSAIDs and 14 days of analgesics demonstrated that the long term use of CS confirmed that in real life the efficiency and the safety profile made it a safe approach taking into consideration the high risk profile (Gastro-intestinal, cardiovascular, etc..) of the other OA symptomatic treatments.