Unwanted side-effects of a drug therapy are well known to oral medicine specialists and other colleagues. Usually they manifest itself as dry mouth, taste disturbances, various allergic or toxic reactions on the lips and/or in the oral cavity. However, the list of the drugs which might induce unwanted reactions is everyday becoming longer as more and more drugs are introduced on the market. Certain problems when diagnosing and reporting unwanted side effects of the drugs exist as only accurate method of diagnosis is repeated drug use in controlled clinical setting where fatal consequences due to the anaphilactic shock could be avoided. We report a side effect reaction to tiotropium bromide (Spiriva) cap used with HandiHaler manifesting itself as an oral ulceration in a 65 yrs old male. On the third day of drug intake the patient developed oral ulceration two times in a period of few months. Other medications he has been using for several years. To our knowledge this is a first report as an oral side-effect of this drug used for treatment of chronic obstructive pulmonary disease (COPD).