Effect of petal Crocus sativus aqueous and ethanolic extracts and diclofenac on formaldehyde induced arthritis in hind paw of rats. The inflammation was produced by subaponeurotic injection of 0.1 ml of 2% formaldehyde in the right hind paw of the rats on the first and third day. The animals were treated daily with the extracts or diclofenac intraperitoneally for 10 days. All agents were administered intraperitoneally. Each point represents the mean ± S.E.M. of change of hind paw size for 6 rats. Only the ethanolic extracts and diclofenac were effective compared to control (normal saline), Tukey-Kramer.