To observe the effect of Chinese herbal medicine on the salivary glands of patients with head and neck cancer during radiotherapy (RT). Fifty cases with head and neck cancer were randomly divided into observation group treated with RT plus Chinese herbal medicine and control group treated with RT alone. The level of mouth dryness, the flow and secretion speed of salivary amylase were measured before and during the RT. The severity of mouth dryness increased and the flow and secretion speed of salivary amylase declined during RT. The mouth dryness curve of patients in Chinese medicine group was significantly more flattened than that of the control group after RT. The flow and the secretion speed of salivary amylase of the observation group were significantly higher than those of the control group at 20 Gy, 40 Gy and 60 Gy. Chinese herbal medicine used in this study was effective to relieve the severity of mouth dryness and to protect the salivary glands of patients with head and neck cancer during RT.