Propagermanium (INN), also known by a variety of other names including bis(2-carboxyethylgermanium) sesquioxide and 2-carboxyethylgermasesquioxane, is an organometallic compound of germanium[2] that is sold as an alternative medicine.

It is a polymeric compound with the formula ((HOOCCH2CH2Ge)2O3)n. The compound was first synthesized in 1967 at the Asai Germanium Research Institute[3] in Japan.

It is a water-soluble organogermanium compound used as raw material in nutritional supplements.

The compound displays low toxicity in studies with rats.

This article about alternative medicine is a stub.