Since 1897, a number of cases of amblyopia from the use of extract of Jamaica ginger have been reported in medical journals, two of which having appeared within the last month. In all cases the cause of the symptoms has been credited to the ginger constituent, and some speculation has been indulged in as to how it could produce the retrobulbar neuritis or whatever other lesion was assumed to be its underlying pathologic condition. Aside from these observations, there is no evidence of any such special toxic action of ginger. It may, if taken in excess, be irritating to the stomach or throat, but it has otherwise no record to place it among the active poisons to the nervous system. This fact has been one of the puzzles to the reporters of these cases. Alcohol in excess, especially with tobacco, can cause the symptom, but the ginger-essence drinkers do not appear to have imbibed enough alcohol to thus account for it; at least it was not so credited. Now, however, there comes a report from Baltimore that certain manufacturers or wholesale druggists have been putting out on the public an essence of ginger the alcoholic constituent of which is methyl alcohol, or possibly what is called methylated spirit, instead of the more expensive ethyl alcohol, a substance which Casey A. Wood2 and others have shown to be quite capable of producing amblyopia, not merely when ingested internally, but also when inhaled or otherwise absorbed in its concentrated form. This, if true, and it is said that the accusation is backed by the Medico-Chirurgical Faculty of Maryland, will go far to account for the misfortunes of the ginger-essence-topers who are said to exist in large numbers in the dry towns of Maryland, West Virginia and Pennsylvania. The way of the transgressor whose appetite for alcohol leads him to indulge in drug substitutes is hard in many ways, and this is only one of them. It is likely, moreover, that the transgressing druggists may also find themselves embarrassed with damage suits and a more or less dilapidated reputation.
Jamaica-Ginger Drinkers' Amblyopia. Arch Ophthalmol. 2003;121(9):1237. doi:10.1001/archopht.121.9.1237