A small herpes at the corner of the mouth of a two-year-old baby is usually considered to be due to allergy, bacterial stomatitis, and herpes of the mouth and lips. It is recommended to go to the hospital for a detailed examination to identify the cause of the disease, can be treated by oral or topical medication. 1, allergy: a small herpes in the corner of the baby’s mouth, and accompanied by edema, itching and other symptoms, may be the skin mucosa contact allergens, allergic reactions occur. In this regard, the oral treatment of sodium cromoglycate, sodium montelukast, prednisone and other drugs can be prescribed, but also the use of boric acid solution, salicylic acid and other drugs for local application, so as to improve the symptoms; 2, bacterial stomatitis: baby corner of the mouth a small herpes, and accompanied by erosion, redness and other symptoms, may be from the baby frequently lick the corner of the mouth with the tongue, or finger friction corner of the mouth, resulting in the occurrence of bacterial stomatitis. In this regard, you can use erythromycin ointment, gentamycin hydrochloride ointment, etc. for anti-infection treatment, and with chlorhexidine acetate solution, saline, etc. for local wet compresses; 3, herpes labialis: the baby has a small herpes at the corner of the mouth, and accompanied by fever, fatigue and other symptoms, may be caused by herpes simplex virus infection caused by herpes labialis. In this regard, you can use acyclovir ointment for local application as prescribed by your doctor. For severe damage to the oral mucosa, gargling with compound chlorhexidine solution can be prescribed, and for severe pain, lidocaine, benzocaine and other creams can be prescribed.