Argemone mexicana L. Papaveraceae. Mexican poppy

Mexican prickly poppy. In India it is called Satyanashi meaning 'devastating'. Herbaceous annual. Distribution Western US, West Indies and Mexico. The seeds yield 35% argemone (aka katkar) oil, contains up to 50% of toxic alkaloids including sanguinarine and dihydrosanguinarine. Mustard oil, used for cooking in India, Mauritius and Fiji, contaminated with as little as 1% katkar oil has caused numerous epidemics of Epidemic Dropsy, caused by proteinuria and consequent hypoalbuminaemia with fluid retention, pitting oedema and congestive cardiac failure, anaemia, skin pigmentation, retinal haemorrhages, glaucoma and shortness of breath. Total depletion of antioxidants especially vitamin E and A (tocopherol and retinol) occurs. Death rate is 5%, but with symptomatic treatment recovery usually occurs within three months. Contamination of wheat flour, in South Africa, with the seeds of Argemone mexicana caused the same illness. Most mustard seeds are black and indistinguishable from argemone seeds, so farmers are encouraged to grow yellow seed mustard so contamination can easily be seen when the seeds are inspected prior to oil extraction. Yellow seed mustard oil does not mix well with argemone oil so can also be detected at the oil stage. Photographed in the Medicinal Garden of the Royal College of Physicians, London.