The purpose of this study is to determine if the traditional Chinese herbal compound (Huo-Luo-Xiao-Ling Dan, or HLXL) is effective in treating OA of the knee in addition to participants current OA of the knee treatment(s) and also to determine the best dosage of HLXL that is safe and well tolerated.

The specific aims of this project are:

1. To determine whether HLXL improves pain and/or function in patients with OA of the knee who continue to have symptoms despite receiving standard analgesic and/or anti-inflammatory treatment,
2. To identify an optimal dosage of HLXL, among two dosages, as determined by pain relief and/or functional improvement, in a dose-escalation, placebo-controlled double-blind randomized phase II clinical trial, in conjunction with indicia of safety and tolerability in patients with OA of the knee who are receiving standard analgesic and/or anti-inflammatory treatment,
3. To explore mechanisms of action of HLXL, correlating changes in biological markers of suppression of systemic inflammation with changes in clinical response

Inclusion Criteria:

• Age 40 years or above
• Diagnosis of OA of the knee of at least 6 months duration fulfilling American College of Rheumatology criteria
• Pain in at least one knee of at least moderate severity (Likert scale [none, mild, moderate, severe, extreme] or VAS pain score of at least 40 [0-100]) on most (at least 15) days of the previous 1 month
• Taking analgesic or nonsteroidal anti-inflammatory agents for control of pain
• Documented radiographic changes of osteoarthritis of the knee (Kellgren-Lawrence grade greater than or equal to 2 at the time of screening)
• Stable on arthritis medications for previous 1 month
• Willingness and ability, with help of a caregiver if necessary, to comply with treatment and follow-up procedures
• Use of effective contraception if woman of childbearing potential
• Signed consent statement

Exclusion Criteria:

• Intra-articular (IA) corticosteroid injection of either knee within a 3 month interval immediately prior to baseline screening
• IA hyaluronates in either knee within the past 6 months
• Tidal lavage or arthroscopy of either knee within the past 12 months
• Medical condition, in the judgment of the examiner and/or study investigators, that may preclude safe participation in protocol or prevents completion of the study, such as: uncontrolled angina and/or congestive heart failure, severe chronic obstructive pulmonary disease, active treatment for cancer, major psychiatric disease, other severe systemic disease, or significant abnormalities on screening physical examination and laboratory tests that reveal clinically important abnormalities of hematological, cardiac, pulmonary, metabolic, renal, hepatic, gastrointestinal or other systems
• Use of any constituent herb in HLXL within the past 3 months
• Current use of Chinese herbs for arthritis
• Use of oral prednisone in the past 30 days
• Current use of anti-coagulants (coumadin, heparin, aspirin >325 mg per day).
• Use of any investigational drug within the past 30 days
• Inflammatory arthritis (e.g., rheumatoid or psoriatic arthritis)
• Currently participating in another intervention research study
• Unwilling to be randomized
• Plan to move residence away from the immediate area within the next 2 months
• Drug or alcohol abuse sufficient to hinder compliance with treatment or follow-up procedures
• Pregnant or lactating
• Exclusive use of a wheel chair
• Surgery in either knee in past one year

8-weeks