Listeriosis is a foodborne disease. Bacteria of genus Listeria are responsible for this disease, especially Listeria monocytogenes which is a gram-positive bacterium and is active in the conditions needed to preserve food. The Mortality rate of listeriosis is 24%. Listeriosis is a serious threat to pregnant women and persons who are Immuno deficient. Symptoms of listeriosis are fever, flu, brain abscess, the tremor, Cranial nerve deficits, respiratory distress, jaundice, rash, or lethargy, etc. Diagnosis is done by culturing the organism from the blood and in the treatment, many antibiotics are given alone or sometimes in combination with two or more. Treatment of trimethoprim/sulfamethoxazole (TMP/SMX) is given as alternate to patients who have allergies with using penicillin.