Inclusion Criteria:

- Negative pregnancy test

- Fertile patients must use effective contraception

- No active infection

- No severe malnutrition

- No more than 2 prior chemotherapy regimens:

- Prior combined modality therapy (e.g., full-dose chemotherapy with
radiosensitizing chemotherapy and radiotherapy) is considered 1 prior regimen if
all therapy was delivered as part of 1 comprehensive treatment plan

- More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin)
and recovered

- No other concurrent chemotherapy

- At least 6 months since prior radiotherapy to the lung parenchyma or mediastinum and
no evidence of radiation pneumonitis on chest CT scan

- At least 4 weeks since other prior radiotherapy and recovered

- No prior radiotherapy to more than 50% of marrow volume

- No concurrent radiotherapy

- Histologically confirmed solid tumor for which gemcitabine is a treatment option OR
for which no efficacious therapy exists

- Must meet criteria for 1 of the following:

- Measurable disease:

- At least 1 unidimensionally measurable lesion at least 20 mm by
conventional techniques OR at least 10 mm by spiral CT scan

- Nonmeasurable disease, including any of the following:

- Small lesions (less than 20 mm by conventional techniques OR less than 10
mm by spiral CT scan)

- Bone lesions

- Cytologically positive pleural or peritoneal disease

- Elevated tumor markers (e.g., carcinoembryonic antigen, CA 125, CA 19-9, or
other tumor marker)

- Multinodular or confluent nonmeasurable pulmonary, hepatic, adrenal,
intra-abdominal, or skin metastases

- No active CNS metastases

- Previously treated CNS metastases must be stable with no symptoms for 4
weeks after completion of treatment AND patient must be off steroid therapy
or on a stable dose for at least the past 2 weeks

- No known leptomeningeal metastases

- Performance status:

- ECOG 0-1

- Hematopoietic:

- Absolute neutrophil count at least 1,500/mm3;

- Platelet count at least 100,000/mm3

- Hepatic:

- Bilirubin no greater than 1.5 mg/dL;

- SGOT no greater than 2.5 times upper limit of normal

- Renal:

- Creatinine no greater than 1.5 mg/dL OR

- Creatinine clearance at least 50 mL/min

- Cardiovascular:

- None of the following within the past 6 months:

- Myocardial infarction;

- Unstable angina;

- Transient ischemic attack;

- Cerebrovascular accident

- No new cardiac arrhythmia possibly related to cardiac ischemia;

- No large and potentially symptomatic pericardial effusion;

- No cardiac disease that would preclude study participation

- Pulmonary:

- No pulmonary embolism within the past 6 months;

- No large and potentially symptomatic pleural effusion;

- No pulmonary disease that would preclude study participation

- Gastrointestinal:

- No intractable emesis;

- No grade 2 or greater chronic diarrheal disease within the past 6 months

- Not pregnant or nursing