subacute myelo-optic neuropathy subacute myelo-optic neuropathy subacute myelo-optic neuropathy (smon) is an iatrogenic disease of the nervous system leading to a disabling paralysis, blindness and even death. its defining manifestation was as an epidemic in japan during the 1960s: the japanese government estimated 11,000 were affected; however, the college of medicine at the university of tokyo put the number at 30,000, citing a lack of preservation of medical records for longer than five years and a lack of cooperation from doctors as the reasons for the discrepancy. on august 3, 1978, the tokyo district court ruled that the cause of smon is clioquinol. its manufacturer, ciba-geigy, has publicly stated that "medical products manufactured and sold by us have been responsible for the occurrence of in japan, we extend our apologies." subacute myelo-optic neuropathyspecialtyneurology smon was first observed and diagnosed in sweden 1966, by the pediatrician and neurologist olle hansson. clioquinol was marketed as a prophylaxis to tourist diarrhoea. dr. olle hansson was in the front line, fighting for a ban of clioquinol. doctors in many countries boycotted ciba-geigy for many years. not until 1985 was the pharmaceutical withdrawn. dr hansson died a few months later. the day of his death, may 23, is observed as the anti-hazardous drug day in several parts of the world.