Inclusion Criteria:

- Patient must have histologically proven, pathologically verified and surgically
incurable(unresectable, recurrent, or metastatic) gastric/gastroesophageal junction
carcinoma. Gastric lymphoma and Gastrointestinal stromal tumor(GIST) are ineligible
for this study. At least 6 unstained paraffin-embedded pathologic specimen slides
will be required for the COX-2 expression assays.

- Patient must have bidimensionally measurable disease as defined in Section 10.1a. All
measurable lesions must be assessed (by physical examination, CT scan, radionuclide
scan or plain X-ray) within 30 days prior to registration. The patient's disease
status must be completely assessed and reported.

- All patients must undergo a CT of abdomen and chest within 30 days prior to
registration.

- Patients with brain metastases are NOT eligible for this study. It is not mandatory
to obtain brain CT or MRI on all patients. However, patients who exhibit
neurological symptoms or have pulmonary metastases on radiographic studies must
obtain brain CT w/ IV contrast or MRI prior to registration to ascertain the presence
of brain metastasis.

- Patients must NOT have received capecitabine or oxaliplatin. Prior use of cisplatin,
carboplatin, 5-FU are permitted. Prior systemic therapy must have been completed at
least 30 days before registration.

- Patients may have received prior radiation therapy. Radiation therapy must have been
completed at least 30 days before registration.

- Patients may have received prior surgery. Prior surgery must have been completed at
least 30 days before registration.

- Patients must have a Zubrod Performance Status of 0-2.

- Pregnant or nursing women are not eligible to participate in this trial because the
safe use of these drugs in pregnancy have not been established. Urine pregnancy test
must be done prior to the study.

- Patient must NOT have known allergic reaction to sulfonamides

- Patient must NOT have known allergic or other adverse reaction to celecoxib

- Patient must NOT have persistent peripheral neuropathy

- Patient must NOT have known hypersensitivity reactions to 5-FU or platinum

- Patient must NOT have active gastric/duodenal bleeding

- Patient must NOT have had a sensitivity reaction to aspirin or other NSAIDS
[experiencing asthma, urticaria, or allergic-type reactions after taking aspirin or
other NSAIDs]