DISEASE CHARACTERISTICS:

* Histologically or cytologically confirmed locally advanced, locally recurrent, or metastatic colorectal adenocarcinoma not curable by surgery or radiotherapy

* Histological or cytological requirement waived in patients who developed radiological or clinical evidence of metastatic cancer after a prior surgical resection unless:

* More than 5 years has elapsed since primary surgery OR
* Primary cancer was stage I or II
* Site of primary lesion must be or have been confirmed endoscopically, radiologically, or surgically to be or have been in the large bowel
* Measurable or evaluable disease
* No CNS metastases or carcinomatous meningitis

PATIENT CHARACTERISTICS:

Age:

* 18 and over

Performance status:

* ECOG 0-2

Life expectancy:

* At least 12 weeks

Hematopoietic:

* Absolute granulocyte count at least 1,500/mm\^3
* Platelet count at least 100,000/mm\^3
* Hemoglobin at least 9.0 g/dL (transfusion allowed)

Hepatic:

* Bilirubin no greater than 1.5 mg/dL
* AST no greater than 5 times upper limit of normal (ULN)
* Alkaline phosphatase no greater than 5 times ULN

Renal:

* Creatinine no greater than 1.5 times ULN

Cardiovascular:

* No uncontrolled hypertension
* No unstable angina
* No symptomatic congestive heart failure
* No myocardial infarction within the past 6 months
* No serious uncontrolled arrhythmia
* No New York Heart Association class III or IV cardiac disease

Pulmonary:

* No interstitial pneumonia or extensive and symptomatic interstitial fibrosis of the lung
* No pleural effusion or ascites that cause respiratory compromise (grade 2 or worse dyspnea)

Other:

* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* No active or uncontrolled infection
* No symptomatic sensory peripheral neuropathy
* No known allergy to platinum compounds
* No history of gastrointestinal bleeding unless it is determined to be acceptable by the enrolling physician
* No other prior or concurrent malignancy within the past 3 years except nonmelanoma skin cancer, carcinoma in situ of the uterine cervix, or other resected malignant tumor with less than a 10% probability of tumor relapse within 3 years of diagnosis
* No medical or psychiatric conditions that would preclude study
* No colonic or small bowel disorders with uncontrolled symptoms of more than 3 loose stools per day
* Colostomy or ileostomy allowed at investigator's discretion

PRIOR CONCURRENT THERAPY:

Biologic therapy:

* Prior adjuvant immunotherapy for resected stage II-IV disease allowed if adjuvant therapy concluded at least 1 year before documentation of recurrent disease
* No concurrent sargramostim (GM-CSF)

Chemotherapy:

* No prior chemotherapy for advanced colorectal cancer
* No prior standard adjuvant chemotherapy for rectal cancer
* Prior adjuvant fluorouracil for resected stage II-IV disease allowed if adjuvant therapy concluded at least 1 year before documentation of recurrent disease

Radiotherapy:

* See Disease Characteristics
* At least 4 weeks since prior major radiotherapy (e.g., chest or bone palliative radiotherapy)
* No prior radiotherapy to more than 15% of bone marrow
* No prior standard adjuvant radiotherapy for rectal cancer

Surgery:

* See Disease Characteristics
* At least 4 weeks since prior major surgery (e.g., laparotomy) (2 weeks for minor surgery) and recovered
* Insertion of a vascular access device not considered major or minor surgery

Other:

* No other concurrent investigational agents