Allyl propyl disulfide is an organosulfur compound with the chemical formula C3H5S2C3H7. It is a volatile pale-yellow liquid with a strong odor. It is a major component of onion oil and is used in food additives and flavors.[1]
Allyl propyl disulfide is present in garlic and onion. When onion or garlic is sliced, the substance evaporates and causes eyes to irritate.[2] When garlic or onion is cooked, it also evaporates, ridding them of the spicy taste, and leaving a sweet taste.