Properties : Yellow mercuric oxid is a light orange-yellow, amorphous powder, odorless and having a somewhat metallic taste. It is permanent in the air, but turns darker on exposure to light. It is nearly insoluble in water and in alcohol.

Incompatibilities: Yellow mercuric oxid is incompatible with acids, which dissolve it, forming mercuric salts.

Action and Uses: Yellow mercuric oxid is employed externally as a stimulant and parasiticide. Its chief use is in blepharitis, phlyctenular conjunctivis, etc., in which it acts as a stimulant.

Dosage: Yellow mercuric oxid should be used in the strength necessary to stimulate without producing unnecessary irritation. An ointment varying in strength from 0.5 to 2 per cent, should be prescribed. Some ophthalmologists recommend even weaker preparations.