The fruiting bodies of the edible mushroom Lactarius salmonicolor (Russulaceae) collected from the wild were extracted with solvents of increasing polarity and evaluated for their antioxidant capacity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. Additionally, their total phenolic content was evaluated by a modification of the Folin-Ciocalteu method. The methanol extract showed the most potent radical scavenging activity (inhibition of 36.7% of DPPH at 3 mg/mL and 6.8 mg gallic acid equivalents/g of dry extract), and was further fractionated. Total phenolics and antioxidant activity found to be significant higher in the fractions of increased polarity. The phytochemical investigation which was performed by chromatographic and spectrometric techniques led to the isolation of nine compounds from the methanol extract and the identification of 10 fatty acids and fatty acids esters from the dichloromethane extract. Evaluation of the antioxidant activity of isolated compounds showed p-hydroxybenzoic acid (4) to be the most active. Among the various compounds found, the rare azulene type 7-acetyl-4-methylazulene-1-carboxylic acid (1) has been identified, which had been isolated only once before from L. deliciosus. Therefore, this compound seems to have some chemotaxonomic value for Lactrarius species exuding orange to red milk.