DPYD and stomatitis: The US food and drug administration (FDA) and European medical agency (EMA) approved drug label of capecitabine warns for the unexpected, severe toxicities like stomatitis, hand-foot syndrome (HFS), diarrhoea, mucosal inflammation, neutropenia in the deficiency of DPYD enzyme and states that no dose has been proven safe in patients with complete absence of DPYD enzyme.