I-Orcein (i-Orcein, i-archil, i-orchil, i-lacmus, i-litmus, i-orcein, i-orsin, i-litmus, i-E182) - amakristalu ansundu amnyama. Ashintsha umbala abe bomvu endaweni ene-acidic kanye noluhlaza okwesibhakabhaka endaweni ene-alkaline. Ifomula yekhemikhali C28H24N2O7.
Isithasiselo asifakwanga ohlwini “lwezithasiselo zokudla zokukhiqiza ukudla” kwi-Sanitary and Epidemiological Rules and Regulations (SanPiN 2.3.2.2364-08) ngo-2008.