Inclusion Criteria:

- History of any size adenoma, known adenoma on present exam, or colon cancer within
the last 6 years

- Scheduled for colonoscopy

- Ability to understand and the willingness to sign a written informed consent document

- Willingness to forego PEG laxative during the study period; if the patient has been
on a consistent dose of non-PEG laxative for 90 days prior to study entry, the
participant may continue those laxatives; participants must agree to restrict
additional laxative use to the rescue medication (bisacodyl) provided

- ECOG performance status 0-1 (equivalent to Karnofsky >= 70%)

- Leukocytes >= 3,000/uL

- Absolute neutrophil count >= 1,500/uL

- Platelets >= 100,000/uL

- INR =< 1.5

- Total bilirubin =< 1.5 X institutional ULN

- AST (SGOT)/ALT (SGPT) =< 1.5 X institutional ULN

- eGFR > 45

- BUN < 40

- Women of child-bearing potential must agree to use adequate contraception (hormonal
or barrier method of birth control; restricting intercourse to a surgically
sterilized partner; abstinence) for the duration of study participation; should a
woman become pregnant or suspect she is pregnant while participating in this study,
she should inform her study physician immediately

- If patients are on a dose of cardioprotective aspirin, they must have been on a
stable dose for three months prior to colonoscopy and agree to remain at that dose
for the six months duration of the study; in addition, patients must agree to limit
therapeutic NSAID use (e.g. pain relief) to no more than 30 cumulative days during
the six month duration of the trial

Exclusion Criteria:

- Average of > 2 bowel movements per day for the 90 days preceding study entry as
assessed by self-report at baseline

- Average consistency of stools described as watery or loose for the 90 days preceding
study entry as assessed by self-report at baseline

- Systemic chemotherapy for any cancer within 18 months prior to enrollment or evidence
of active malignant disease

- Radiation to the rectum within 24 months prior to enrollment

- Polyethylene glycol use within 3 months of enrollment (except as part of colonoscopy
preparation)

- Systemic corticosteroid use

- Anticoagulant therapy

- Inflammatory Bowel Disease

- Removal of the rectum

- Evidence of proctitis (radiation, IBD, infectious, etc.) by history or endoscopy

- Other investigational agent use within 30 days prior to enrollment

- History of adverse reactions attributed to compounds of similar chemical or biologic
composition to polyethylene glycol, bisacodyl or methylene blue

- Uncontrolled intercurrent illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements

- Pregnancy

- Patient must not have used suppository medication or enemas for the three months
prior to the trial or for the duration of the trial except as directed for
colonoscopy or flexible sigmoidoscopy procedure bowel preparation