The product data explicitly states that Glutathione-SR is contraindicated in individuals with a known history of hypersensitivity to any of its ingredients
(PubMed) Hiltunen JK, Autio KJ, Schonauer MS, Kursu VA, Dieckmann CL, Kastaniotis AJ
[2] Iron supplements may cause a grayish-black stool that should be distinguished from melena, [3] as should black coloration caused by a number of medications, such as bismuth subsalicylate (the active ingredient in Pepto-Bismol), or by foods such as beetroot, black liquorice, or blueberries
Dying a thousand deaths: redundant pathways from different organelles to apoptosis and necrosis
Miller, E
They should always ask for the ingredients list and verify the clinician's medical credentials