Although its protective effect is contested and the risk of contracting tuberculosis is rather low nowadays, BCG vaccination is frequently performed. Changes of strain repeatedly led to an increased complication rate. In Austria between 1990 and 1991, of 3386 newborn babies (Strain Pasteur) 116 developed lymphadenitis 3 to 28 weeks after vaccination. The affected children received four types of treatment: nothing specific, isoniazid, or surgery with and without isoniazid. Surgical treatment was found to be necessary in 96 cases. Bacilli were successfully grown in culture in 46% of cases up to week 20 after vaccination; but later than 20 weeks no culture became positive. All cultured bacteria were isoniazid-sensitive. From our data we drew the following conclusions: isoniazid therapy did not prove successful when inflamed lymph nodes exceeded a certain size. Suppurative lymphadenitis in lymph nodes exceeding 1.0 to 1.5 cm usually led to infiltration or even perforation of the skin. Surgery prevents these complications and significantly reduces healing time. Adjuvant isoniazid therapy cannot be recommended, except for generalized BCG tuberculosis.