The present invention relates to novel imidazole derivatives having a positive allosteric GABA
B
receptor (GBR) modulator effect, methods for the preparation of said compounds and to their use, optionally in combination with a GABA
B
agonist, for the inhibition of transient lower esophageal sphincter relaxations, for the treatment of gastroesophageal reflux disease, as well as for the treatment of functional gastrointestinal disorders and irritable bowel syndrome (IBS). The compounds are represented by the general formula (I) wherein R
1
, R
2
, R
3
and R
4
are as defined in the description. For example, R
1
may be phenyl, R
2
may be dimethylamino pyrrolidin-1-yl, R
3
may be alkoxy and R
4
may be alkyl, ai arylalkyl, aryloxyalkyl, aryloxy or heterocyclylalkyl.