Lacrimal occlusion with punctal or canalicular plugs have been used to treat dry eye disease for more than 40 years. Indeed, punctal plugs constitute a safe and effective tool to retain the natural tear film and prolong the effect of tear substitutes. A wide variety of plugs is available, differing in their design, location (punctal versus canalicular) and their resorbability. There indications have increasingly broadened, and they are now one of the treatment options for numerous ocular surface diseases. Current research focuses on using punctal plugs for extended delivery of drugs to the ocular surface. This review addresses physiology of lacrimal drainage, available models of punctal plugs, their indications, practical details of prescribing and placing punctal and canalicular plugs, and possible complications.