We present the case of an 82-year-old woman with severe keratouveitis secondary to exposure to the plant Euphorbia cyparissias during the month of August. Despite copious irrigation of both eyes, she developed a case of Euphorbia keratouveitis that was typical in its course. Exposure to plant sap from this species should be treated much like an alkaline chemical injury as the pH of the ocular surface may be elevated. E. cyparissias should be carefully handled as it may result in keratouveitis, especially in early autumn.