In 1766, the agricultural scientist Giovanni Targioni Tozzetti described for the Grand Duchy of Tuscany, the wild and cultivated plant species that could be used, in times of famine, to increase the quantity of flour or vegetable mass in bread making. These wild plants can be defined as wild edible plants (WEPs) or “alimurgic species”, a concept usually traced back to Giovanni Targioni Tozzetti himself. The 342 plant names mentioned in the text are in the Tuscan vernacular, so a research work was done on bibliographic sources from the 1800s in order to match them with their current nomenclature. This process led to an “alimurgic flora” repertoire based on the writing of Targioni Tozzetti; and a comparison with our AlimurgITA database of 1103 wild edible plants used in Italy. It is particularly interesting that in his short treatise, Giovanni Targioni Tozzetti identified eight toxic plants (corresponding to 14 species), indicating how to eliminate the poisonous substances from their useful roots. We treat them in detail, examining their current and past use, their geographical distribution in Italy, and their eventual toxicity. We obtained 343 matches, of which 198 were reliable (certain matches) and 145 possessed some degree of uncertainty (due to generic or collective vernacular names). Among the 198 certain identifications, 140 species are present in the AlimurgITA database (92 mentioned for Tuscany) and 58 are not; for bread-making there are only documentary traces of 53 species for Italy and 7 for Tuscany. Moreover, among the total 198 species, 84 showed some degree of hazard. Researching edible toxic spontaneous species allows: (1) investigation, from an unusual perspective, of a historical period in which the poor conditions of some social strata led to finding unusual solutions to food provision; (2) idea generation to re-enable potentially useful WEPs whose use has been lost. Making a virtue of necessity!