On 2014 Dec 10, David Keller commented:

This study was funded by the manufacturer of MiraLax brand polyethylene glycol laxative

Braintree Laboratories, the manufacturer of MiraLax, funded this year-long open-label study of the safety of their product. However, given the large number of consumers who ingest polyethylene glycol 3350 on a chronic basis, often for many years, it would be helpful to obtain longer-term follow-up of the participants in this study. In addition, a larger and longer-term study, not manufacturer-funded, is warranted, given the unrestricted over-the-counter sale and unmonitored use of PEG-3350 by consumers.

Ethylene glycol is known to be a toxic substance, as are its short multimers, di-ethylene glycol and tri-ethylene glycol. Even if polymerization of 54 ethylene glycol monomers, to an average molecular weight of 3350, renders the resulting long-chain polymers harmless, can we rely on this polymerization to hold up under all circumstances? Human digestion is largely the process of depolymerization of polysaccharides and polypeptides. To what extent does PEG-3350 de-polymerize to ethylene glycol or its toxic short multimers, during digestion or during preparation of the laxative? Are trace amounts of toxic monomers or short multimers produced under any circumstances - including mixture with various beverages and at various temperatures which consumers might use?

Even in the absence of de-polymerization, how much PEG-3350 is found in the serum and urine of humans during chronic daily use? What subtle long-term effects might be caused by the presence of trace amounts of these chemicals in the diets of diverse humans, for years on end? Only a larger, longer-term, independently-funded study can answer these questions.

On 2014 Dec 10, David Keller commented:

This study was funded by the manufacturer of MiraLax brand polyethylene glycol laxative

Braintree Laboratories, the manufacturer of MiraLax, funded this year-long open-label study of the safety of their product. However, given the large number of consumers who ingest polyethylene glycol 3350 on a chronic basis, often for many years, it would be helpful to obtain longer-term follow-up of the participants in this study. In addition, a larger and longer-term study, not manufacturer-funded, is warranted, given the unrestricted over-the-counter sale and unmonitored use of PEG-3350 by consumers.

Ethylene glycol is known to be a toxic substance, as are its short multimers, di-ethylene glycol and tri-ethylene glycol. Even if polymerization of 54 ethylene glycol monomers, to an average molecular weight of 3350, renders the resulting long-chain polymers harmless, can we rely on this polymerization to hold up under all circumstances? Human digestion is largely the process of depolymerization of polysaccharides and polypeptides. To what extent does PEG-3350 de-polymerize to ethylene glycol or its toxic short multimers, during digestion or during preparation of the laxative? Are trace amounts of toxic monomers or short multimers produced under any circumstances - including mixture with various beverages and at various temperatures which consumers might use?

Even in the absence of de-polymerization, how much PEG-3350 is found in the serum and urine of humans during chronic daily use? What subtle long-term effects might be caused by the presence of trace amounts of these chemicals in the diets of diverse humans, for years on end? Only a larger, longer-term, independently-funded study can answer these questions.