Introduction Conjunctivitis is an inflammation of the conjunctiva, a thin translucent mucous membrane, characterized by a dilatation of the conjunctival vessels. Causes leading to conjunctivitis are diverse, being drug related one of them. Case report We report a case of an 80-year-old man with a diagnosis of relapsed stage IV colon cancer who developed a severe conjunctivitis, scar ectropion with lack of tissue and eversion of the subconjunctival conjunctiva after being treated with capecitabine. Management and outcome Capecitabine was discontinued and pharmacological treatment was initiated with a complete resolution of the symptoms. Discussion Ocular toxicity derived from the use of systemic fluorouracil has been widely described in the literature, as well as the relationship between the use of capecitabine and the appearance of conjunctivitis. However, the development of severe conjunctivitis with other complications has not been previously reported. Monitor patients closely and perform full medication assessment should be undertaken when a patient reports visual changes to manage toxicity in the early stages. Following the patient evaluation and evolution and based on the Karch Lasanga algorithm modified by Naranjo, the adverse reaction is considered as probable.