Antituberculous treatment could be continued by using steroid as adjunctive therapy in two patients showing febrile reaction to antituberculous drugs in spite of desensitization therapy. Case 1 (39-year-old man) was admitted to our hospital with positive sputum-smear and bilateral cavitary tuberculosis (b II 2) on chest X-ray. He showed fever of 38-39 degrees C after 8 days of HREZ treatment. Desensitization therapy of RFP with the combined use of prednisolone was enforced, since the exothermic reaction continued in spite of stopping the 4 medicines, and the treatment became possible. Case 2 (40-year-old woman) was admitted with positive sputum-smear and bilateral cavitary tuberculosis (b II 2) on chest X-ray. The administration of drugs was stopped as temperature rose to 38-39 degrees C after 12 days of HREZ treatment. Though the DLST of INH was positive, the treatment with INH became possible by the combined use of PSL.