AbstractHelicobacter Pyloriis a gram negative bacterium that has been shown to be the causative organism in some gastric and duodenal ulcers. It is the most common cause of antral gastritis and has been linked to the development of distal gastric carcinoma and low grade gastric lymphoma. Identification in a gastric biopsy and prompt treatment with antibiotics, can lead to a speedy recovery for the patient. Unfortunately this organism stains poorly with standard hematoxylin and eosin techniques and special staining methods can be lengthy. The usual demonstration methods are Steiner and Romanowski type stains. Toluidine blue has been used as a rapid method for the demonstration of these organisms, but the contrast is generally very poor. We have developed a counterstain for toluidine blue that shows deep blue organisms on a yellow background. The combined procedure takes about 30 min. (The J Histotechnol19:131 1996)