Diethylene Glycol (commonly abbreviated as DEG) is an organic compound with the chemical formula C₄H₁₀O₃. It is a colourless, odourless, and hygroscopic liquid with a sweet taste, typically miscible with water, alcohol, and many organic solvents.

Monoethylene glycol (MEG) is an odorless, colorless, clear and viscose liquid with a sweet taste, which is produced from the reaction between water and ethylene oxide. It is miscible with water, alcohols, and many organic compounds, and has the chemical formula of C2H6O2.

Mono Propylene Glycol (MPG) serves as a solvent, connects and stabilises insoluble fluids, reduces the freezing point in water, increases the boiling point, and offers outstanding stability with high flash and boiling points. MPG is chemically neutral, i.e. it usually does not react with other substances.

• MEG
• PEG
• TEG
• DEG

Polyethylene glycols (PEGs) are condensation polymers of ethylene oxide and water with the general formula H(OCH₂CH₂)_nOH. They are the most commercially important type of polyether. The low molecular weight compounds up to 700 are colorless, odorless viscous liquids with a freezing point from -10˚C (diethylene gycol), while polymerized compounds with higher molecular weight than 1,000 are wax like solids with melting point up to 67˚C. While PEGs with different molecular weights find use in different applications and have different physical properties (e.g. viscosity) due to chain length effects, their chemical properties are nearly identical.

The numbers that are often included in the names of PEGs indicate their average molecular weights, e.g. a PEG with n=9 would have an average molecular weight of approximately 400 and would be labeled PEG 400. Most PEGs include molecules with a distribution of molecular weights, i.e. they are polydisperse.

PEGs are soluble in water and most organic solvents.

Triethylene glycol, TEG, or triglycol is a colorless odorless viscous liquid with molecular formula HOCH₂CH₂OCH₂CH₂OCH₂CH₂OH. It is used as a plasticizer for vinyl polymers. It is also used in air sanitizer products, such as “Oust” or “Clean and Pure”. When aerosolized it acts as a disinfectant.