Sub-antimicrobial dose doxycycline posses known anti-inflammatory effects that are separate from their antibacterial mode of action.This mode of action has lead to the routine use of sub-antimicrobial dose doxycycline for treating inflammatory or autoimmune diseases, such as rosacea, periodontitis and multiple sclerosis.We confirmed on the basis of predecessors' studies that low dose oral doxycycline and topical application of doxycycline can accelerate corneal epithelium healing after ocular surface burn, effectively inhibit inflammation mediated corneal new angiogenesis.Its mechanism of action is about downregulate MMP2 and nitric oxide synthase.