In a case sure to send retail pharmacy corporate-types scurrying to board room meetings to ensure their bases are covered, a Northern District of California federal judge held that Walgreens’ Co.’s 15 year-long pattern of filling opioid prescriptions for customers without performing adequate due diligence as to the medical legitimacy of the prescription substantially contributed to the opioid crisis in San Francisco. As a result, Walgreens must—to a degree later to be decided in court—abate the opioid crisis in San Francisco that it helped to create. While the scope of Walgreen’s court-mandated abatement is not yet known, the fact that a retail pharmacy was held to be at least partially liable for the down-the-line harm stemming from its customers’ misuse of the prescriptions it fills is a headline holding, carrying with it the potential to raise the stakes of the everyday retail pharmacy work of filling prescriptions. In good news for other retail pharmacies generally and for Walgreens retail pharmacies in other states, the holding turned on two hinges that could swing the door of liability shut in other scenarios: 1) the habitual, 15 year-long practice of San Francisco Walgreens of skirting the due diligence required of them under the federal Controlled Substances Act (“CSA”), and 2) the application of California-specific nuisance law that many other states have yet to apply in the same way.