Polyethylene glycol (PEG) is approved by the FDA for use as a carrier or matrix in foods, cosmetics, and pharmaceuticals, including injectable, topical, rectal, and nasal formulations. PEG exhibits minimal toxicity and can be fully excreted from the body via the kidneys (for PEG <30 kDa) or feces (for PEG >20 kDa). It is non-immunogenic, and antibodies to PEG only develop in rabbits when PEG is combined with highly immunogenic proteins.