The objective of the present study is to study paracetamol effects on social pain and empathy under standardized international conditions (ICH-GCP) for planning, conduction and reporting of clinical pharmaceutical studies in humans. The study included MRI imaging of brain activity, analysis of genomic biomarkers potentially explaining interindividual variation. It is controversial whether the effects are of immediate nature or develop during a period of about 10 days. Therefore, the study is separated into two study phases. Single dosing (SD) is applied in study phase 1 and multiple-dosing (MD) in study phase 2. The study compares paracetamol with placebo and in the study phase 1 also with ibuprofen as analgetically active control.

Inclusion Criteria:

1. Written informed consent obtained prior to study.
2. Willingness to meet the study instructions and to co-operate with the study personal.
3. No clinically relevant pathological findings in any of the investigations at the screening visit; minor deviations of laboratory values from the normal range may be accepted if judged by the investigator to have no clinical relevance.
4. Body weight not less than 48 kg and body mass index (BMI) not less than 17 kg/m² and not greater than 32 kg/m².

Exclusion Criteria:

1. Pacemaker devices, implantable or external ones.
2. Involvement in the planning and conduct of the study (applies to staff directly employed at the study site / department).
3. Known pregnancy or lactation period.
4. History of alcohol and / or drug abuse and / or any abusive use of medicaments.
5. Any disease affecting liver or kidney or impairment of the liver or kidney-function.
6. History of severe hypersensitivity reactions, anaphylaxis, psychiatric or neurologic disorder.