Quantitative computer-assisted evaluation of thioctic acid-induced sprouting in Neuro-2a cells reveals a clear dose dependence with respect to several parameters of sprouting. At first predominantly the length of main sprouts per cell (neurites from cell soma to first branching) and the number of branchings per cell are increased. With the higher dosages, the length of branches per cell rises considerably, too. In contrast, the degree of branching (mean length of neurites per branching) seems to be independent of the concentration of thioctic acid. The capacity of thioctic acid to induce sprouting is discussed in terms of the involvement of SH groups and with regard to regeneration phenomena as they may occur in diabetogenic neuropathy.