The article describes the case of a six-year-old boy with previously undiagnosed glucose-6-phosphate dehydrogenase (G6PD) deficiency who developed life-threatening haemolysis induced by application of henna to his skin. Topics covered include the results of the physical examination, the symptoms experienced by the Sudanese boy consistent with haemolysis due to G6PD deficiency and the life-threatening risk of henna.