The objective of the present study is to obtain information about the safety and tolerability of BIIF 1149 BS, to determine the pharmacologically active dose (range) by performing a citric acid challenge test and to obtain preliminary pharmacokinetic data

Inclusion Criteria:

• Participants should be healthy males
• Age range from 21 to 50 years
• Within +- 20% of their normal weight (Broca-Index)
• In accordance with Good Clinical Practice (GCP) and local legislation each volunteer is supposed to give his written informed consent prior to admission to the study
• Each subject will have his medical history taken and will receive a complete medical examination (incl. blood pressure and pulse rate measurements) as well as a 12-lead Electrocardiogram (ECG)
• A citric acid provocation test will be performed to determine the cumulative dose of citric acid which causes at least three coughs. If there will not be at least three coughs after inhalation up to the highest citric acid concentration of 32 % the volunteer will be replaced by a new person
• Haematopoietic, hepatic and renal function test will be carried out in the laboratory
• The subjects will fast for 12 hours before collection of specimens for all laboratory evaluations. The above mentioned examinations will be performed within 14 days before the first administration of the test substance

Exclusion Criteria:

• Volunteers will be excluded from the study if the results of the medical examination or laboratory tests are judged by the clinical investigator to differ significantly from normal clinical values
• Volunteers with known gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
• Volunteers with diseases of the central nervous system (such as epilepsy) or with psychiatric disorders
• History of orthostatic hypotension, fainting spells or blackouts
• Chronic or relevant acute infections (especially respiratory infections, cough)
• History of allergy/hypersensitivity (including drug allergy) which is deemed relevant to the trial as judged by the investigator
• Intake of a drug with a long half-life (>= 24 hours) within ten half-lives of the respective drug before enrolment in the study
• Use of any other drugs which might influence the results of the trial during the week previous to the start of the study
• Participation in another study with an investigational drug within the last two months preceding this study
• Smoker (> 10 cigarettes or 3 cigars or 3 pipes/day)
• Inability to refrain from smoking on study days
• Alcohol abuse (> 40g/day)
• Drug abuse
• Blood donation (>= 100 ml) within the last 4 weeks
• Excessive physical activities (e.g. competitive sports) within the last week before the study