The authors present, in the context of actual management of glaucoma, the role of antimetabolites in addition to glaucoma filtering surgery. The main reason of failure in filtration surgery is the excessive postoperative scarring response at the contact episclera-subconjunctiva. The antimetabolites inhibit the fibroblastic growth, therefore providing a great number of adequate filtering blebs. Indications, surgical techniques, complications and risks are also discussed.