A method for treating or alleviating allergic disease in a mammal in need thereof having administering to the mammal a therapeutically effective amount of a pharmaceutical composition having phycocyanin is provided. A method for modulating balance between Th1 and Th2 immune response in a mammal in need thereof, having administering to the mammal an effective amount of phycocyanin, wherein immune response of the mammal is skewed toward the Th1 immune response is also provided. Phycocyanin from Bangia atropupurea (Ba-PC) is identified to regulate mammalian immunological response indicating that Ba-PC can direct skewed immune response toward Th1 response through modulating DC function, increase proliferative activity of antigen-specific T cells and alleviate airway inflammation, confirming that phycobiliproteins are effective in treating allergic disease.一種治療或減緩哺乳動物的過敏性疾病的方法，其中包含對哺乳動物投藥以一治療有效劑量的藥學組成物，該藥學組成物係包含藻藍素。一種調節哺乳動物Th1與Th2之間的免疫反應的平衡的方法，其中包含對哺乳動物投藥以一有效劑量的藻藍素，藉以令哺乳動物的免疫反應趨向發生Th1免疫反應。取自於頭髮菜的藻藍素已被認為可調節哺乳動物的免疫反應，其證實頭髮菜可經由調節樹突狀細胞作用使得免疫反應直接趨向發生Th1免疫反應，並且可增加抗原特異性T細胞的增殖活性以及減緩呼吸道發炎作用，證實藻膽蛋白應用於治療過敏性疾病的確是有效用的。
