Barbados cherry (BC) (Malpighia glabra Linnaeus) is a functional fruit that is consumed to prevent disease. It is used as an adjuvant in the treatment of several diseases, and acts as an antianemic, an appetite stimulant, a wound healer, an anti-inflammatory, a mineralizer, an antifungal, and an antioxidant agent. Several chemotherapeutic agents, such as cyclophosphamide, may result in undesirable side effects, and generate mutations in normal cells. Thus, the present study evaluated the antimutagenic potential of the fresh (BCN) and frozen (BCF) juices of BC pulp, with and without concomitant administration of cyclophosphamide, using a chromosomal aberration test system in the bone marrow cells of Wistar rats treated in vivo for 24 h. The results showed that neither the BC juice (0.4 mg/mL) alone, nor that with concomitant cyclophosphamide (1.5 mg/mL), were cytotoxic. BC has potential as an antimutagenic, and statistically reduced the percentages of chromosomal alterations induced by cyclophosphamide when administered simultaneously (BCN: 80.75%; BCF: 88.26%), pre-treatment (BCN: 86.85%; BCF: 87.32%), or post-treatment (BCN: 90.14%; BCF: 86.85%). This was due to the antioxidant activity of the fruit and the action of its bioactive compounds, which may have inhibited cyclophosphamide metabolism or scavenged the free radicals generated by this compound. Thus, attenuation of cyclophosphamide-induced mutagenicity suggests that the consumption of fresh or frozen BC should be encouraged for the prevention of disease, and for the maintenance and promotion of health.