Filtration surgery is still the major operative intervention to glaucoma. The failure (recurrence) rate of the surgery remains high due to the scarring of the filtration zone as the result of fibroblast hyperplasia. To improve the success rate of the surgery, a variety of anti-fibrotic agents have been used in the clinic, which may be potentially accompanied by unwanted adverse reaction/side effect and complications. With better understanding of the scarring process, progress on the development of anti-scarring agents with high efficiency but less side effects has achieved to improve the outcome of filtration surgery. Novel anti-fibrotic agents are under investigation recently, including anti-vascular endothelial growth factor,pirfenidone, suramin, sphingosine-1-phosphate antibody, suberoylanilide hydroxamic acid, tissue inhibitor of metalloproteinase, microRNA, gene therapy and nano-drugs. The researches regarding the effectiveness and safety of these novel agents are still preliminary. Further studies on the pharmacokinetics of these drugs needs to be carried out, including the dosage, timing and frequency of drug administration.