Jatropha curcas (Euphorbiaceae) is a multiple purpose lacticiferous plant with potential for biodiesel production and medicinal uses. There is in the literature different analyses about the toxic and cytogenotoxic effects of J. curcas extracts, but few information about latex toxicity. In addition, few models were employed to evaluate the toxicity response to J. curcas latex, and the toxicity in in vivo mammal’s model has not been tested yet. The cytotoxic, mutagenic and antimutagenic potential of J. curcas latex were investigated using mouse bone marrow erythrocytes. The results indicated a cytotoxic and mutagenic potential of this latex to mammalian cells. But, when J. curcas latex was co-administrated with doxorubicin (DXR – chemotherapy medication), a reduction in the number of micronuclei was observed, indicating an interaction between J. curcas latex and DXR. The interaction of latex with DXR can cause a reduction in the activity of this drug and impair the treatment of its users. Moreover, there is a lack of data on herb–drug interactions, what should be more investigated to safeguard the wellbeing of patients.