Plant secondary metabolite (PSM) content in food attracts considerable attention for health consideration. As PSM in dairy products primarily depends on animal feeding, this study aimed to evaluate the phenolic content of milk and cheese from goats fed with plants commonly used as forage in mountain farming systems. Siriana goats were fed indoor with freshly cut Avena sativa in pureness for 13 days. Milk and whey tank samples were daily collected contextually with cheese-making (Caciotta cheese) and stored at –20°C. Offered herbage was daily collected and stored at –20°C, freeze-dried and ball milled. Phenolic compounds were analysed as UV-absorbing compounds (UAC), on plant, milk, whey and cheese samples using HPLC-DAD. Twenty-five peaks were found in plants, 26 in milk, 26 in whey and 26 in cheese. Milk and whey UAC profiles were similar with benzoic acid derivatives as major compounds, and different to that of cheese. Although several flavones were found in Avena sativa, none was found in the corresponding milk, whey and cheese.