All study subjects (receiving DROGLICAN or untreated control) will be allowed to take paracetamol and oral NSAIDs excluding COX2 inhibitors to relief knee pain. Patients will be asked to use these "rescue medications" only when needed during the trial, beginning by Paracetamol (up to 3g/day) and NSAIDs as a second-line medication, and will be told to reduce their use if they do not feel the need for them. The use of rescue treatments during the month prior to each visit will be recorded by the investigator in a Case Report Form (CRF). All other treatments for osteoarthritis will be forbidden during the course of the study.