Orcein-alcian blue staining: a new technique for demonstrating acid mucins in gastrointestinal epithelium.

Orcein-alcian blue staining, a new method for the simultaneous demonstration of sulphated and sialomucins in gastrointestinal epithelium was compared with the standard high iron diamine-alcian blue technique. Sections were oxidised with potassium permanganate and decolourised in oxalic acid. They were stained with orcein for four hours, differentiated for a few seconds in acid alcohol, and then counterstained with alcian blue for half to one minute. There was a good correlation of results between the two methods. Orcein-alcian blue is a safer, cheaper, and quicker method than high iron diamine-alcian blue which can be safely introduced into routine laboratories for the study of acid mucins in the gastrointestinal diseases.