The relative drying rate of samples (RDR), which is the ratio of the drying rate of pretreated samples to that of untreated ones, might be used as a tool to investigate the damage to cells of agroproducts induced by high-pressure treatment. Damage to cells induced by high pressure was estimated by comparing the RDR after high-pressure pretreatment with the RDR after chloroform-vapor, heat, and freeze-thaw pretreatments of Japanese radish samples. The RDR after high-pressure pretreatment was similar to the RDR after chloroform-vapor pretreatment, and was lower than for heat, and for freeze-thaw pretreatment. For agroproducts, high-pressure treatment is thus comparatively moderate.