Application of procyanidin B2 in medicaments

The invention provides an application of procyanidin B2 in preparing medicaments for protecting bone marrow cells. In one embodiment, the procyanidin B2 is a compound with content of 100%. In another embodiment, the procyanidin B2 is a 0.05-1.5 wt% mixture, preferably 0.05-0.4 wt% mixture. According to the application provided by the invention, preferably, the mixture also contains at least one of catechin and sanguiin. The procyanidin B2 can protect bone marrow hematopoietic stem cells, relieve mouse bone marrow DNA (deoxyribonucleic acid) inhibition caused by radiotherapy or chemotherapy, and increase white blood cell count.