The use of Huang Lian (Rhizoma coptidis) and Huang Bai (Cortex phellodendri) and products containing the alkaloid Berberine has been prohibited in Singapore since 1972 based on sporadic cases and circumstantial evidence that Berberine could cause kernicterus in glucose-6-phosphate dehydrogenase (G6PD) deficient neonates. The gene discussed is G6PD; the disease is kernicterus.