To investigate safety, tolerability, pharmacokinetics and pharmacodynamics of BI 187004 following multiple dose administration over 14 days.

Inclusion criteria:

1. Type 2 diabetes mellitus
2. Current treatment with no more than one anti-diabetic drug (except for insulin and GLP-1 analogues)
3. Males or post-menopausal or surgically sterilised females
4. Age from 20 and to 70 years
5. HbA1c less or equal to 8.5%
6. BMI 28-40 kg/m2
7. Subjects must be able to understand an comply with study requirements

Exclusion criteria:

1. Any finding in the medical examination (including BP, PR or ECG) deviating from normal that the investigator considers to be of not acceptable clinical relevance
2. Repeated measurement of systolic blood pressure greater than 160 mm Hg or diastolic blood pressure greater than 95 mm Hg
3. Myocardial infarction, stroke or transient ischemic attack within 6 months prior to informed consent
4. Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders besides type 2 diabetes, hyperlipidaemia or medically treated hypertension
5. Surgery of the gastrointestinal tract that might affect absorption and elimination of the study drug
6. Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or relevant neurological disorders besides polyneuropathy
7. Chronic or relevant acute infections (e.g. HIV, hepatitis)