Abstract This paper describes the early history of magnetochemistry: the search for chemical effects of magnetism in the nineteenth century. Some early researchers, such as Johann Wilhelm Ritter, attempted to reproduce with magnets the effects that had been produced by electricity and Volta’s battery. For several decades, researchers successively reported positive results and denied claims concerning the effect of magnetism in oxidation, electrolysis, reduction of metals from saline solutions, crystallisation, change of colour of vegetable tinctures and other chemical reactions. (...) In the two last decades of the nineteenth century some effects were accepted as real, and a thermodynamic theory of the influence of magnetic fields upon chemical reactions was developed. Finally, Dragomir Hurmuzescu was able to create reproducible experiments and measured the electromotive force between two electrodes, with or without the presence of magnetic fields, confirming the existence of the phenomenon and obtaining results compatible with the theoretical predictions. Afterwards, this magnetochemical effect was accepted as real, but the effect was weak and its practical importance was negligible. The subject was gradually forgotten. Content Type Journal Article Pages 1-26 DOI 10.1007/s10698-011-9127-8 Authors Roberto de Andrade Martins, Department of Physics, State University of Paraiba, Campina Grande, PB, Brazil Journal Foundations of Chemistry Online ISSN 1572-8463 Print ISSN 1386-4238. (shrink)