Propylene glycol, often abbreviated as PG, is a synthetic organic compound with the chemical formula C3H8O2. It is a colorless, odorless, and tasteless liquid with a variety of applications across different industries. Propylene glycol is classified as a diol or double alcohol due to its two alcohol (-OH) functional groups.

One of the most common uses of propylene glycol is as a humectant in food and pharmaceutical products. It helps retain moisture, preventing products like food, cosmetics, and medicines from drying out. In the food industry, it is also used as a food additive with the designation E1520.

In addition to its role in the food and pharmaceutical industries, propylene glycol is employed in the manufacture of antifreeze and de-icing solutions for vehicles and aircraft. It has low toxicity compared to its ethylene glycol counterpart, making it a safer choice for applications involving potential human or environmental exposure. Propylene glycol is also found in various personal care products, including cosmetics, skin creams, and oral hygiene products.