Dendrobium cannot be taken by patients who have not injured their yin in the early stage of warm-heat disease, who have not transformed dryness in wet-warm disease (warm disease caused by feeling dampness and heat), or who have deficiency and coldness in the spleen and stomach. Dendrobium is a kind of Chinese herbal medicine with effect of yin tonic, which has the effect of benefiting the stomach and generating fluid, nourishing yin and clearing heat, and is mainly used in clinic for heat disease with fluid injury, insufficient gastric yin (insufficient yin fluid in the stomach), dry mouth and thirst, little food and dry vomiting, yin deficiency and fire, not subsiding of deficiency fever after illness, darkness of the eyes and uncertainty, bone vapor and laborious heat, impotence of sinew and bone, and so on. Dendrobium can converge the evil, so that the evil does not reach the outside, so patients with warm-heat disease should not be taken in the early stage, and can help dampness, so dampness and warmth has not yet been turned into dry people can not be taken. Patients with stomach and kidney deficiency and heat are suitable to take dendrobium, but patients with spleen and stomach deficiency and cold should not take it. The toxicity of dendrobium is relatively low, and the poisonous dose of dendrobium can cause convulsions. Dendrobium is a kind of Chinese medicine with unique pharmacological effects, before taking it, it is recommended to consult a professional doctor to exclude the contraindications of medication, so as not to cause adverse consequences.