Study aim: Investigate of the effect of N-compound subectance on knee pain and function in patients with knee osteoarthritis Design: A clinical trial with a control group, with parallel groups, double-blind, randomized, phase 2-3, performed on 25 patients. Excel software was used for randomization. Settings and conduct: The study site is the rheumatology clinic of Ali-Ibn Abi-Taleb Hospital in Rafsanjan. The study population includes patients with osteoarthritis of the knee referred to the mentioned rheumatology clinic. In this double-blind study, the drug in both groups is the same in color and shape and is prepared in the laboratory by an expert. The container containing oil is filled with one of the two intervention substances or placebo and then is coded. Only the coder who does not participate in the study knows the relevant code, and the analysis is done by another person. In this method, the researcher and the treatment staff of those who communicate with the patients do not know the type of intervention or treatment. Participants/Inclusion and exclusion criteria: Inclusion criteria: age of 45-70 years old; Non-inclusion criteria: underlying diseases; Hypersensitivity to herbal medicines; smoking Intervention groups: The control group: The placebo (paraffin, a substance with a similar shape, taste, and smell as intervention drug) is used for two months. Intervention group: Composite substance (olive oil - turmeric - coriander oil and egg yolk), which are received by a physician and it is recommended to massage the drug on the knee for 3 to 5 minutes daily. Main outcome variables: Inflammation; knee pain