The present invention discloses a non-polysaccharide constituent for positively regulating the immune system in the therapy of allergic diseases. The non-polysaccharide constituent is extracted from genus Dendrobium by incubating in alcohol and extracting using solvents with different polarity.本發明所揭一種非多醣體組合物,對於過敏性疾病係具有正向免疫調控之功效。而該非多醣體組合物係萃取自一石斛屬植物,其中,萃取方法係為先取將一石斛屬植物浸泡於一醇類中,再分別以不同極性之溶劑萃取而得之。