Inclusion Criteria:

- Female patients must have histologically or cytologically indicated breast cancer
(stages I, II, III) eligible for adjuvant anthracycline chemotherapy [FEC100 or
AC-Taxol(paclitaxel) every 21 days.

- HER2 negative or HER2 positive breast cancer by immunohistochemistry (IHC3+) and/or
fluorescent in-situ hybridization.

- Eastern cooperative oncology group (ECOG) performance status = 0, 1, 2

- Age ≥ 18 years old.

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

- The effects of L-carnitine on the developing human fetus at the recommended
therapeutic dose are unknown. For this reason, women of child-bearing potential must
agree to use adequate contraception prior to study entry and 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 treating physician immediately.

Exclusion Criteria:

- Patients with evidence of metastatic breast cancer.

- Resting LV ejection fraction < 50%.

- Patients having received previous anthracycline therapy or contraindication to
anthracycline.

- Patients having a contraindication to L-carnitine therapy

- Dexrazoxane therapy at the time of enrollment.

- Patients with abnormal baseline bloodwork:

- hemoglobin ≤ 100 mg/L

- platelets ≤ 100 x 10^9/L

- white blood cells ≤ 4 x 10^9/L

- creatinine, AST, ALT, bilirubin > 1.5 x the upper normal limits

- Participation in another randomized clinical trial.

- Patients having significant cardiac disease (previous myocardial infarction,
congestive heart failure, or hemodynamically significant valvular heart disease) that
would limit compliance with study requirements.

- Patients taking medication that may affect LV function (b-blockers, amiodarone,
ACE-inhibitors, calcium channel blockers, or digoxin).

- Patients with symptoms of heart failure.

- Patients unable to participate in a study requiring long term follow up.

- Pregnant or lactating women.