Endoscopy and biopsy of the caudal gastrointestinal tract were performed pretreatment and on the last day of a @-day treatment period with ( @ ) oral carprofen ; ( @ ) carprofen and the proton-pump inhibitor lansoprazole ; ( @ ) carprofen , liquorice extract , and a herbal solution that contained extracts of thyme , icelandic lichen , hyssop , and saponariae root ; ( @ ) robenacoxib ; ( @ ) robenacoxib and lansoprazole ; ( @ ) robenacoxib , liquorice extract , and herbal solution ; or ( @ ) an empty gelatin capsule .