Ocular side effects of systemic fluorouracil include excessive lacrimation, due to punctal and canalicular stenosis and fibrosis. Obstruction of the tear ducts after systemic therapy with fluorouracil is more frequent than is assumed. Five patients with breast cancer and punctal or canalicular stenosis are presented. Although complaints of epiphora usually resolve two weeks after cessation of systemic therapy, local antibiotics and steroids may be indicated. In patients with persisting complaints, and patients treated with fluorouracil for a prolonged period of time, prophylactic intubation of the tear ducts with silastic tubes has been advocated. (Conjunctivo)dacryocystorhinostomy may be unavoidable.