In fact, thousands of antibiotic substances have been found, but most are not useful in medicine because of being too toxic to people or to animals.
وقد اكتُشفت آلاف المضادات الحيوية ،‏ لكن معظمها لا يفيد طبيا لانه مسم جدا للناس او للحيوانات .‏