A number of anticancer drugs, especially molecularly-targeted drugs, have been 
developed every year. Drug-induced interstitial lung disease(DILD)is a common 
adverse event associated with molecularly-targeted drugs, and it is therefore 
important to obtain information about the DILD risks of each drug. Recently, 
all-case surveillance of new drugs have been carried out frequently as 
post-marketing surveillance. This allows one to understand the accurate status 
of DILD, such as its incidence rate and prognosis. The diagnosis of DILD is 
often difficult because there is no specific diagnostic approach. It is 
necessary to distinguish DILD from various other diseases including infectious 
disease, cancer progression, congestive heart failure, etc. Among those, 
respiratory infection is an important disease in the differential diagnosis of 
DILD, because patients receiving anticancer drugs are likely to be susceptible 
to infection. As for the treatment of DILD, the general rule is the 
discontinuation of the offending drug, and if necessary, the administration of 
corticosteroid is indicated. However, an exceptional treatment is required for 
DILD caused by mTOR inhibitor, for which we must take account of the adequate 
management.