It is not necessary to use boiling water for boiling water, but usually 80 to 90 degrees Celsius water can be used to dissolve the medicine before letting it cool to the right temperature for taking. For powdered or granular medicines, it is often not possible to take the medicine before drinking the water. Often the instructions for such medicines will be labeled as boiling water. It is not necessary to use boiling water at 100 degrees Celsius to take the medicine, usually water above 80 degrees Celsius can fully dissolve the medicine. After the medicine is fully dissolved in boiling water, it can be taken when the medicine returns to the appropriate temperature. Boiling water is a common way of taking medicines. For medicines that are labeled to be taken with boiling water, it is important to fully dissolve them before taking them to achieve the best results.