Although the frequency of self-medication among Mexican migrants has been well-documented in the public health literature, the multiple reasons for this practice are poorly understood. Most studies point to migrants' cultural preferences for Mexican medications, their prior experiences in countries where antibiotics are loosely regulated, and their lack of access to health care as the primary factors behind their self-medication. Based on participant observation and in-depth interviews with 23 Mexican migrants in a farm working community in the interior of California, we argue that occupational vulnerability is an equally important factor that encourages self-medication. All 23 of our interviewees reported having engaged in some degree of self-medication, notable in this location 8 h from the US-Mexico border. Among interviewees, occupational vulnerability represented an even more important factor influencing self-medication than lack of health insurance or lack of legal documentation. While interviewees did express a preference for Mexican medications as more potent and effective, this did not necessarily translate to a preference for using them without a doctor's supervision. Finally, we show that rather than remaining unaware of the risks of following this custom "transported from Latin America", Mexican migrants devised an elaborate hierarchy of resort of the safest self-medication practices to follow.