Some Medical Benefits of Quince Preserve. the use of quince preserve strengthens the heart. improves mental and spiritual health. produces fresh blood. controls blood pressure. it is the best tonic for pregnant and lactating women. it protects against non-seasonal diseases. reduces the risk of heart attack. reduces the spread of cancer. corrects the irregular heartbeat. strengthens the lungs. helps in weight loss. frequently used for congestive heart failure. quince preserve increases breast milk. it eliminates muscle cramps. removes bladder stones. improves brain function. strengthens the liver. frequently used in eliminating cysts, improves digestion by correcting intestinal secretions.