Thermally-inhibited starches and flours are used in conventional water-based adhesives such as corrugating, cigarette, remoistenable, kraft adhesives. The starches or flours are thermally-inhibited by dehydrating the starch to anhydrous or substantially anhydrous and then heat-treating the starch or flour for a time and at a temperature sufficient to inhibit the starch and improve its viscosity stability. The starch or flour may be thermally or non-thermally dehydrated (e.g., by alcohol extraction or freeze-drying). Preferably, the pH of the starch is adjusted to at least a neutral pH prior to the dehydration.