The research was conducted during the year 2022 to estimate the most important active compounds in the different plant parts of some types of hawthorns (Crataegus L.) widespread in northwestern Syria (Aronia, Yellow Azarolus, Red Azarolus, and Monogyna). The plant material was collected during the growth period. Flavonoids were estimated in the dry matter of the leaves, flowers, and fruits of the studied hawthorn types, vitamin C in the dry flowers and fresh fruits, carotenoids in the dry fruits, total acidity (TA%), and total soluble solids (TSS%) in the fresh fruits. The results showed that the value of flavonoids in the leaves reached 29.66, 15.76, 14.42, and 14.66 mg/g DM in the studied hawthorn types Monogyna, Aronia, Red Azarolus, and Yellow Azarolus, respectively. The leaves outperformed the flowers and fruits in their flavonoid content in most types, as the average flavonoid content of the leaves, flowers, and fruits in the different types was 18.60, 17.71, and 10.90 mg/g DM, respectively. The highest value of flavonoids (29.66 kg/g) was in the leaves of the Monogyna type, and the lowest value (6.23 mg/g) was in the fruits of the Red Azarolus type. As for vitamin C in the dried flowers of the different types, its value reached 1018.6, 917.5, 814.9, and 799.1 mg/100g, while the value of vitamin C in fresh fruits was 11, 8.14, 7.04, and 6. 53 mg/g, in Monogyna, Aronia, Yellow Azarolus and Red Azarolus, respectively (in dried flowers and fresh fruits). The Monogyna type outperformed the other types of vitamin C content, whether in dried flowers or fresh fruits. As for carotenoids, the values were 0.202, 0.077, 0.093, and 0.156 mg/cm³, respectively, for the types Monogyna, Red Azarolus, Yellow Azarolus, and Aronia. The Monogyna type outperformed the other types in the carotenoid content of its fruits. As for the total acidity, the Red Azarolus type outperformed the other types. The total acidity values were 2.54, 1.94, 1.8, and 0.46% for Red Azarolus, Yellow Azarolus, Aronia, and Monogyna, respectively. Finally, there were no significant differences between the total soluble solids content of the fruits of the different types, as the TSS values reached 24.60, 23.33, 21.27, and 20.97%, in the Red Azarolus, Yellow Azarolus, Monogyna, and Aronia types. Respectively.