Quince is a vitamin bomb. Contains vitamins A, C, E, B1, B2, B6 and PP. The seeds of quince contain fructose, glucose, potassium, calcium, phosphorus, and copper. Be careful with them though. From the seeds of quince you can boil healing potion, but should not be crushed. Inside of the seeds of quince contain poisonous substance glycoside amygdalin.