Natural sweet chestnut tannins (NCT), hot water-extracted from untreated wood and membrane-concentrated to 17% DM (13% tannins), are presently diffusing in tobacco crop in Central Italy, as a starter treatment in transplant irrigation water, at 2-5 percent concentrations. In comparative tests, this treatment has proved to be as good as an ordinary starter fertilizer application (10-34-0 banded at crop transplanting) to boost early plant growth and rooting, with interesting side effects in soils prone to nematode infestation. In this latter case, the first application in transplant water is completed by further 4-5 treatments in microirrigation. The complete treatment program requires, on average, 35-45 kg/ha of actual tannins, at costs comparable with, or lower than, ordinary nematicides. However, chemical nematicides cannot be used (or have temporary and limited permission of use) under the agro-environmental-oriented crop programs, which are presently extending to most crops in Europe. So NCT may represent an interesting, natural alternative when agrochemical residue-free crop products are sought. We are presently investigating the activity of several fractions of the raw NCT to (possibly) identifying: those more active for their (i) nutritional effects (on P-Fe-Zn- Mn), due to their acidifying and complexing action; (ii) action on nematodes; and (iii) antioxidant and antimicrobial activities for several applications, included the nutraceutical and bio-medical ones. Chestnut tannins are presently labeled in Italy for agricultural uses as a natural soil and water corrective, iron complexing agent, and nitrogen retarder. They have been applied also for labeling as biostimulants, which permits to claim their action in increasing plant tolerance to nematodes. (Reprinted with permission)