Inclusion Criteria:

- Must have at least 2 nevi (each >6 mm diameter) not clinically suspicious for
melanoma that can be biopsied.

- Must be able to receive informed consent and sign an approved consent form that
conforms to federal and institutional guidelines.

Exclusion Criteria:

- The patient is a minor (< 18 years old).

- The patient cannot speak/understand English or Spanish. (NOTE: A Spanish consent form
and certified interpreter can be made available if needed)

- The patient is pregnant. (NOTE: All female patients who have not had a hysterectomy
and are not post-menopausal (i.e. post-menopausal for 1 year and not of child-bearing
potential) will have a urine pregnancy test.)

- The patient is a prisoner, critically or mentally ill, or otherwise incapacitated or
considered vulnerable.

- The patient has history of allergic reaction to NAC.

- The patient has history of severe asthma.

- The patient has been taking NAC or any other oral antioxidant.

- The patient has recent history (i.e., 3 months) of sunless tanning (tanning bed) or
extensive sunburn.