p-Hydroxybenzaldehyde, also known as para-hydroxybenzaldehyde, is an aromatic aldehyde with a hydroxyl group at the para position relative to the aldehyde group. It is a colorless to pale yellow liquid with a sweet, floral odor, often used in the synthesis of various organic compounds and as a flavoring agent in food and beverages. It occurs naturally in some essential oils and is known for its antimicrobial properties. In culinary applications, it can enhance the flavor profile of certain dishes and is also studied for its potential health benefits, including antioxidant activity.