The phenolic compounds from plants have a significant role in human diet as antioxidants. Their main sources are fruits, vegetables and beverages etc. However, by-products from food and agriculture also have valuable amounts of phenolic antioxidants. These phenolic compounds are effective in curing of many diseases including cancer, cardiovascular, contagious, viral and inflammatory diseases. Dietary phenolic contents were compared in various plant materials including rosemary extract, basil extract, laurel extract, cumin extract, ginger extract, extra virgin olive oil, high bush, low bush, cranberry, strawberry, high bush blue berry, low bush blue berry, wild mulberry, black plum skin, rough lettuce, red cabbage, wheat, date, rice kernel, rice bran, honey, red wine, white wine and green tea extract; the phenolics were found in the range of 0.25-147 mg/g, with the exceptionally higher value reported for basil extract (147 mg/g) and the lowest value (0.25 mg/g) for white wine. Among all the investigated fruits, vegetables, commercial fruit juices, beverages and wines, the highest amounts of phenolic contents were found in apple (296.3 mg/100g), mint (399.8 mg/100g), orange (339 mg/100g), instant coffee (146-151 mg/100g) and Italian red wine (3314-4177 mg/100g), respectively.