Key points 1. This is the first report of adult primary herpetic oropharyngitis in the view point of the differences between the two types of herpes simplex virus (HSV). 2. 41 (25 type 1 and 16 type 2) HSV specific antigen positive cases among 68 immunoserologically confirmed adult HSV primary infection cases were investigated. 3. Significantly low incidence of oral lesions and high incidence of nausea were seen in HSV type 2 oropharyngitis cases, that might mean particular correlation vagus nerve and HSV type 2. 4. Significantly increased white blood cell count and high C-reacative protein value were seen in oropharyngitis by HSV type 2. 5. HSV type 2 possibly cause more severe symptoms and higher inflammatory reactions than type 1, without oral lesions.