The present invention, fucoidan, and relates to a pharmaceutical composition or a medical device comprising at least one compound of formula A or B, wherein R1 and R2, which may be identical or different, independently, OH, -CH _3, It is selected from the group consisting of -CF ₃ CH ₂ O-, and CH ₃ O. Such pharmaceutical compositions or medical devices, excessive angiogenesis and / or skin involving fibrosis disorders, such as skin fibrosis, angiofibroma, hamartoma, and those in Tsume囲 fibroma, rosacea, seat acne, atopic dermatitis, scleroderma, psoriasis, and conditions of the skin that occur in association with erythematosus, due especially tuberous sclerosis, and symptoms of skin that occurs in association with tuberous sclerosis treatment and / or it is particularly useful for prophylaxis.