SHEET /m/magnesium-oxide · PubChem CID 14792 · REV 2026.07
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Magnesium oxide from source
MgO · 40.305 g/mol
Magnesia · Granmag · Heavy magnesium oxide · Calcined magnesia
chemical compound naturally occurring as periclase
CategoryNutrient
Fig. 1 · 2D structure RDKit
O=[Mg]
Where you'll find it
Not yet mapped to everyday foods or products.
The dose makes the poison inferred
A reported mouse oral LD50 for Magnesium oxide is 810 mg/kg, the dose lethal to half the animals tested. Scaled by body mass alone:
56.7 g
a median lethal dose scaled to 154 lb (56,700 mg)
“The dose makes the poison” is a cross-species estimate shown as neutral science, not a threshold anyone should act on. Real toxicity depends on the person, not body mass alone.
Toxicity & hazards
Toxicity · LD50
810 mg/kg · low toxicity · LD50 mouse oral from source
The dose lens above scales this to a body weight.
WarningIrritantH319, H335from source