RESUMO
As many natural medicines absorb water at boiling, yields of the decoctions are affected by absorbed water. Therefore, we examined the quantity of imbibition of each crude drug at boiling. We used 75 kinds of crude drugs. After boiling 600ml of water, each natural medicine was boiled for 70 minutes. The medicine was left for 60 minutes, and then boiled again for 20 minutes. The quantity of imbibition of each natural medicine was measured at 10, 20, 30, 40, 60, 130, and 150 minutes. The maximum data among the quantity of imbibition at each point was labeled “maximum quantity of imbibition.” With regard to the maximum quantity of imbibition in natural medicines of plant origin, the range was from a maximum of 69.10g in Chrisanthemi Flos to a minimum of 3.26g in Persicae Semen. The average maximum quantity of imbibition was 22.51±13.00g, and there were large differences among each of the natural medicines. The quantity of imbibition at 10 minutes or 20 minutes was above 80% of each maximum quantity of imbibition on many crude drugs, but that gradually increased over the time course for some crude drugs.