Acquired toxic methaemoglobinaemia.

Eighty Six adult males presented with central cyanosis and constitutional symptoms 2 to 4 hours following ingestion of meal from a common kitchen. On spectrometry methaemoglobin was detected. All recovered fully in 12 to 36 hours on symptomatic treatment. Epidemiological study and toxicological examination revealed that metanil yellow used for colouring the rice was responsible.