The purpose of this case report is to illustrate food intoxication in infants as a consequence of fennel ingestion. Four cases of methemoglobinemia (MetHb) are presented here. Each patient ate homemade fennel puree a few hours prior to arriving to the emergency department with cyanosis unresponsive to oxygen, in the absence of suspected cyanotic heart disease. All 4 patients received treatment with methylene blue and fully recovered. Our cases emphasize that improper handling and storing of vegetables can lead to life-threatening MetHb.